Hey there, all. For various reasons, my group has decided that we're not going to move forward with Essentials. We understand, and are okay, with the fact that it means we really won't be seeing a lot of additional content coming our way. From the DM side, yes, but not so much from the player side of things. What that means is that we've turned a bit more attention to things we've known where somewhat broken for a while now, but had just assumed would be fixed "at some point".
The assassin class is one of those things. Thematically, it can be a lot of fun. Shadows, shrouds, and stabbity goodness - it makes for a great image. The problem is that it's well-known to be weak on the damage side of things (acceptable during heroic tier, but falling greatly behind other strikers in Paragon and Epic tier). Morever, at least for my group, the weapon choices that make the most sense from a mechanical perspective serve only to detract from the theme and vision we have of an assassin. Mechanically, they're best-off using fullblades. Thematically, we want to see daggers, shortswords, darts, and the like.
So we've taken our first crack at fixing these points. Let me know what you think - is it too strong? Too fidly? Not enough? Without further ado...
Assassin Class Feature Changes
The only two direct changes we've made to the class are in the way the shroud works, and in adding an additional feature, "Lethal Weapons". Together, they should help alleviate much of the scaling damage problems the assassin has, as well as reinforce the use of the 'right' weapons.
Assassin's Shroud
The assassin's shroud power functions as normal for the class, except that the damage dealt is changed to 1d6 per tier, per shroud. Thus, a first level shroud deals 1d6 damage, and an epic-level stack of four shrouds deals 12d6 [42avg.] damage (currently, it would do 4d6+24 [38avg.])
The rationale here was to bring the shroud in-line with other striker damage features. While the difference of four average damage doesn't seem like much, the difference in damage on a crit is between 72 and 48 - an extra 50%.
Lethal Weapons
Assassins are masters of using almost anything to kill their target. When using a one-handed weapon, your weapon damage die increases by one size. When wielding a weapon with the off-hand property, your weapon damage die increases by one size. When you are carrying nothing in your off-hand, your weapon damage die increases by one size. These increases stack, to a maximum of 1d12 damage.
Here's one that I'm concerned is too fidly, but it's the simplest we've been able to state it. It serves two purposes. One, it offers a reason for assassins to use weapons that have low damage die, such as daggers and darts. The largest increase you'll see with this class feature is a three-damage-die bump, which brings a 1d4 base weapon up to dealing 1d10. That means that a dagger-wielding assassin using these rules is roughly on par with a core assassin using a greatsword.
The feature also works as a disincentive for using larger weapons. Weapons like warhammers and broadswords get a one-die bump, dealing 1d12 damage without having any real supporting proprties. Most notable normal weapons become the shortsword (1d12, 1d10 dual-wielding), and the scimitar and rapier (1d12, high crit or +3 attack). For superior weapons, the katar is one of your best choices, and that works quite well, thematically.
Looking it over, the nastiest weapons that I could see an assassin using with these rules are the whip (+3, 1d10 reach 2) and the katar (+3, 1d12 high crit). The katar, I'm absolutely fine with - it gives them a small, thematically appropriate weapon that matches the fullblade. The whip, I'm not so sure about, but given that it would cost an extra feat, it probably wouldn't be too broken.
Assassin Feats
We've also devised some new feats. I'm less comfortable here - only one of the three should be available to the class, I think, but I'm not sure which. The first is a rewrite of Brutal Shroud, and adds the high-crit property. The second gives the assassin a bonus against targets while building up a shroud, and the third modifies shroud damage by making the invoking attack much more accurate.
Brutal ShroudHeroic Tier
Prerequisite: Assassin
Benefit: Whenever you make the damage roll for your assassin’s shroud, reroll each die that shows a 1 until it shows a different number. In addition, when you invoke your assassin’s shroud and score a critical hit, the target takes an additional 1d6 damage per shroud.
Enclosing ShadowsHeroic Tier
Prerequisite: Assassin
Benefit: When you attack a target that has at least one of your shrouds on it, you gain a +1 bonus to the attack roll and a +2 bonus to the damage roll. The bonus damage increases to +4 at level 11, and +6 at level 21.
Unerring ShroudHeroic Tier
Prerequisite: Assassin
Benefit: When you invoke your assassin’s shroud on a target, you gain a bonus to the attack roll equal to the number of shrouds minus one.
Finally! Someone else who wants to see the Ossassin attain the glory it SHOULD have had! 
I see exactly ONE thing I'd like to comment on, and that's Enclosing Shadows, which appears to be something that would be as mandatory for assassins as Painful Oath is for avengers... and the latter's a Paragon feat.
...Oh, and on a somewhat related note, I'm given to understand that the assassin's powers themselves are problematic for a Striker? Your thoughts on that? 
I see exactly ONE thing I'd like to comment on, and that's Enclosing Shadows, which appears to be something that would be as mandatory for assassins as Painful Oath is for avengers... and the latter's a Paragon feat.
Hrm, I think you might have a point there, though I'm not sure. I'm going to spit out some quick math, and let me know how you think it works out, number-wise. Let's clarify that you don't receive the bonus from Enclosing Shadows on the round you invoke your shrouds. I think it compares well to the d8 kicker boost feats other classes get. Quick napkin math, just looking at the damage bonus part of the feat.
I'm going to start by assuming that we don't invoke the shrouds on a target until it's got four shrouds, and also that the assassin is attacking that target while building shrouds. Neither of which are entirely accurate, or even the most likely, assumptions, but they do make the feat the most powerful, since the benefit from it applies for three rounds (shroud, shroud, shroud, boom).
In that case, we see +2 damage on round 1 (shroud 1.) +2 damage on round 2 (shroud 2). +2 damage on round 3 (shroud 3). +0 damage on round four (shroud 4, invoked for 4d6 damage). The total benefit added is six damage over four rounds.
A ranger using Hunter's Quarry, with the feat to increase damage die to d8s, does 1d8, 1d8, 1d8, 1d8, for an average of 4.5 damage per round. (This compares to doing d6/d6/d6/d6 without the feat, an average of 3.5 damage/round.) That means the feat, for a ranger, adds a total of four damage over four rounds. Which would mean that the Enclosing Shadows feat is significantly more potent.
Two other things to factor in, though. The d8 damage die bump is identical to the +2 damage/shroud feat on a critical hit. Which is about 5% of the time in heroc tier, and generally about 10% of the time, for a striker, in Paragon/Epic tier. So we're actually comparing 1.5 damage per round for the assassin feat to 1*0.95 + 2*0.05 (1*0.9 + 2*0.1 paragon or later), or 1.05 (1.1) damage per round for the ranger/warlock/other-striker-d8 feat.
The assassin one still pulls ahead, but for the fact that the assassin is required to attack the shroud target - which often isn't optimal, as we've found in my game that the assassin tends to shroud the main target while picking off minions for a few rounds. It also requires the assassin to be hitting the target for four rounds straight, and if any striker is doing that, you're looking at a rare scenario.
Thus, if we assume the assassin invokes shrouds every three rounds, instead, it's 4 damage/3 rounds, or 1.333/round provided by the feat. And if he's shrouding every other round, it's 2 damage over two rounds, or 1/round provided by the feat. Which suggests that it's on par, math-wise. (The numbers do scale equitably in paragon and epic tier. Each additional +2 damage compares to the hike of another d8.)
All said, I think you're right - that one's a bit potent. Probably need to drop the +1 to hit, at the very least, but I'm still concerned that it doesn't lend to the right flavor, forcing the assassin to stick to a single target instead of the minion-dropping-leading-to-nova-round that we tend to see it do currently.
...Oh, and on a somewhat related note, I'm given to understand that the assassin's powers themselves are problematic for a Striker? Your thoughts on that?
As far as this, I don't have as fun - or lengthy - a response. I personally don't think their powers are, in and of themselves, bad. They could certainly use a few more out-of-action powers, as of their entire attack power alotment, only two are not standard actions (and both of those are dailies.) Since strikers do tend to gain a lot of power from being able to make a second, minor or immediate action attack in a round, that does put them behind a bit.
That said, it's also really worth noting that their power list is just really shallow, at the moment. They could plain use more to chose from. But that's not a problem unique to them - a lot of the non-core classes suffer from it.
Anyway, I appreciate the feedback Eisenritter, and hope I didn't respond with too much of a wall-of-text. I'm going to get some sleep on this end - the alarm is going off in 6.5 hours, and I'm not looking forward to it.
Nah, it's good. Like I said, been wanting to see it touched up, but I couldn't be buggered to do it myself 'cus no one ever helps me when I do things like that. 
That said, yeah, I agree with most of it (especially that Lethal Weapons seems a bit fiddly, but that works for now anyway)... and, unfortunately, I don't think we're going to get any more for the Ossassin. Stoopid Essentials....
EDIT: Wait, false alarm.
The only thing I might suggest changing is to limit Lethal Weapons (by the way, why not simply call it Assassin Weapon Talent?) to light blades, and to remove the Assassin's proficiency with military heavy blades. Or maybe take a page from the Rogue, and limit it to specific weapons - katars, kukri, hand crossbows, etc. If you do change Lethal Weapons that way, I'd suggest letting them gain the increased damage die size even when wielding more than one weapon - I don't think there's anything wrong, thematically, with an Assassin dual-wielding daggers or katars, for example.
Why not simply call it Assassin Weapon Talent?
I like that name better than Lethal Weapons.
I'm adapting elements of the -E-ssassin to the -A-ssassin, but some way to encourage Assassins to wield "assassiny" weapons (much as the Barbarian is encouraged to stick with lighter armor, instead of going with heavy) is one thing I'm really looking for.
Generally, I think you're headed in the right direction. Some of the feats seem to push things a bit (namely the attack bonuses), but I don't think they're broken.
In a more perfect world, I'd love to see the Assassin rebuilt on the Monk class's chassis: All Implement powers; Use weapons as implements; some Weapon-specific rider effects.
I'd also settle for simply having set damage dice for Assassin weapon powers - say, 1d8 + Dex damage instead of 1[W] + Dex.
Either of those would leave the option for using oversized weapons, but really give no benefit for doing so.
Without re-writing the majority of the class though, those are somewhat out of reach.
One thing to watch out for with your method: You need to limit it to basic attacks / Assassin powers. A 1d12/high crit katar may not be much for the Assassin, but if he multiclasses Rogue his rogue powers will be dealing lots more damage than a straight rogue would.
What about something that more closely reflects the Executioner's approach? Say...
[Variant A]
When you are wielding a weapon with the off-hand property and have your other hand free, you deal +1[W] damage with melee basic attacks, and all assassin and assassin paragon path powers with the weapon keyword. At 21st level, this increases to +2[W] damage.
The problem there would be that it would tend to front-load the benefits onto at-will powers, and lower damage powers. You could match the damage of a maul with a short sword on at-will powers (1d6 +1d6 for the shortsword; 2d6 for the maul), and surpass the damage of a greatsword or greataxe.
The problem is going to be that encounter and daily powers will still likely favor larger weapons. A 2[W] attack, for instance would yield 2d6+1d6 = 3d6 damage with a short sword, vs. 4d6 damage with a maul, 2d12 damage with a greataxe, or 2d10 damage with a greatsword.
Hm. What about adding an accuracy boost to that effect? I really like the idea of an accurate assassin anyways. So instead...
[Variant B]
When you are wielding a weapon with the off-hand property and have your other hand free, you gain a +1 bonus to attack rolls and deal +1[W] damage with melee basic attacks, and all assassin and assassin paragon path powers with the weapon keyword. At 21st level, the bonus to damage increases to +2[W].
So weapon at-wills would always favor an off-hand[+free hand] weapon, and things would be more even at the encounter/daily level. A 2[W] attack would yield: +4 for 3d6 (short sword); +2 for 4d6 (maul); +2 for 2d12 (greataxe); or +3 for 2d10 (greatsword). Hm. I like that one.
Bah. Too much brainstoming.
community.wizards.com/go/thread/view/758...(community_project_proposal)?pg=1
We're working on the assassin and trying to come up with a whole Shadow source that everyone can enjoy.
Your weapon business is, sadly, way too fidly, and too general. Seems likely to cause interaction problems & balance issues.
Here are some alternatives to consider:
1) come up with one to three 'signature weapons' for each guild, and give that guild specific bonuses with those weapons. This is most elegant, and lets you improve existing guilds, but thematically bonuses dependent on using particular weapons feels more like a 'martial power' gimmick then a 'shadow power' gimmick, and I thought part of the point was to keep their peanut butter out of our spinach dip.
2) leave the current guilds as is, but introduce a couple new guilds with class features that benefit using two weapons or having a hand free or fighting unarmed. Maybe a shadow hand guild themed around using hand signs with a free hand to supplement their weapon attacks with more finely manipulated shadow magic, manifesting as some sort of bonus when attacking the target of your assassin's shroud with a weapon while your off hand isn't carrying or weilding anything, or serpent's fang guild themed around dual weapon use providing more damage and less control for assassins who want that via multiattack powers that interact well with shrouds (ie - at will weapon attack dex vs. AC main hand, if hits W damage and make a secondary attack dex vs. Ref off hand, if hits W damage and apply your assassin's shroud to the target, even if you already used it this turn)
Otherwise, a feat to mitigate the loss of damage from targets dying with shrouds still on them would be nice. And making targets who are unaware of the assassin also unaware of shrouds as a default rather then requiring a feat would be a good call, imo.
As for enclosing shadows, why not just make it an assassin-specific expertise feat? +1 feat bonus to hit and +2 untyped bonus to damage per tier against targets of your assassin's shroud. Gets by implement/feat issues that assassins can have without resorting to the bland 'versatile expertisse' feat. Then again, damage bonus is a bit bland, too, maybe trade it for something more thematic? maybe a per tier stacked bonus to stealth checks against your shroud target? I don't know. Something.
The Perfect Slayer ED for Assassin's make your shroud uber epic at level 30. Yes, I know, you're level 30 and deserve to BE uber epic, but it makes all the other strikers look like sad pandas with your dozens of dice being thrown while the ranger whimpers like a sad dog and throws out 3d6's (d8's hopefully)
Granted, throughout your assassin's career he or she has had to wait to invoke them while the ranger was loldamaging things to the ground so this is pretty much the feature that will garner respect from fellow strikers.