But the game has helped foster such attention seeking geeks as Marilyn Manson... Ok, he's an idiot (IMHO) but he's probably a very rich idiot!
Anyway, I've played a lot of sessions in two different campaigns now... I was a paladin in the one i defected from- a decision I sorta regret nowadays, I've been thinking they could perhaps let me back in. In my current one I play a barbarian. We just hit lvl 6, and we're playing "the red hand of doom" which our DM has upgraded to DD 4. Its a great campaign, lots of stuff to do and you get a feeling your actions really affect events in the world.
I am doing the finishing touches on my own campaign which will take place in a world of my own design. TBH its just the geography, politics and the history that's "all me" the races, gods cosmology etc. are ripped straight from the books but as a very wise swedish saying goes "originality is good- theft works." Bill Gates has made billions in this way... Don't mess with success...
During my forays into the fairy-realms as a player I've come across some problems in DD 4 that I am more than willing to discuss with you lot... In order to milk your intellects for solutions that I am too lazy to figure out for myself.
1. Stop trying to hit me and HIT ME
Problem with the way the DMG wants you to design encounters is that the average party of smart and experienced DD players seems to cut through those like a super-heated adamantium katana through half molten easy spread butter. Our current DM has thought up some really smart solutions, but we haven't quite figured it out yet. It looks like baking a lot of encounters together into one great rumble works ok in the store bought adventures... I.e the monsters in the next room are alerted by the strange howls of terror and dying screams and impacting acid lightningbolts... "What's wrong with Bob? Does he have a toothache or something? Better go check."
Problem with this is that the battles tend to drag out a bit. Once we had a four hour (real time) fight. Your bladder can hold only so much and I'm a nicotine addict, but at the same time you don't want to lend your turn to Mr. Potatohead who will place you out of range for a charge and flanked by two insubstantial clones of Vecna.
The second solution seems to be to throw in monsters that are three-four levels higher than the party- at least as many monsters as party members plus a couple of elites added to the mix... Plus some minions... Problem with this seems to be that there is a thin red line that you can't cross over as DM. Just a a couple of levels of monsters too many and the party is R.I.P. guaranteed. And you don't want to be guilty of designing an encounter that spells certain doom!
I mean which discerning rolegamer has done that after the age of twelve.
Of course you can mess with the figures during the encounter but for me as DM this kills the "suspension of disbelief" that keeps me from playing monopoly instead of DD. If the players are going to face a runescribed dracolich ridden by Kas wielding the Wand of Orcus I want a lump in my stomach based on uncertainty rather than the conviction that they will have to roll up a new character next time. Basically I don't want to be forced into a position where I have to tell the players that they hit when they really missed etc. because this disturbs my delicate DM ego. We are all just actors on the stage of life, etc.
More problems will follow.
As I play a striker in my current campaign I am faced with this problem. My attacks all target AC and this is always the toughest defence of the youropposition. And so I get to roll my die and I have about 50% chance to hit in which case I get to roll a lot of d6 and re-roll every roll of one which is even more fun... BUT
Onstage the controller... He has a lot of bursts and blasts so when we fight he gets to roll a lot more dice... Not to mention the fact that HE always targets defences that are reflex, will etc so he gets to hit more... The strikers drift into a fitful sleep and do not awake until the dawning of a new age where WOTC see that having too many defences means balancing is hard.
Perhaps they don't realize that rolling two to-hit dice means your chance of dealing a crit increases by 100% even!
Say what now?
Not to mention the fact that HE always targets defences that are reflex, will etc so he gets to hit more...
That's why you (assuming you use a weapon) get a proficiency bonus to your attack rolls and the controller isn't. As long as the controller doesn't automatically know the target's lowest defense and have enough powers to target it, things should be fairly even between weapon and implement users in regard to hitting.
Also, learn to love the ways to gain Combat Advantage.
For problem 1 I'd recommend designing higher level encounters like +2 levels up. But be careful about using soldiers more then +3. Just slowly bump things up. But also, sometimes a fair fight is still easy from good rolls. Remember if you make it a hard fight and the PC's get bad rolls then its a TPK so be careful. If your party just used it's last healing power then make sure everyone knows it and consider retreating. Also remember that healing potions are easy to use mid fight, they are only a minor to get out and a minor action to drink, so carry a lot of them.
Is level 6 your highest character? So you're still pretty new right?
Lots of things aren't obvious at first. The books don't explain much about their background reasoning a lot of the time.
An encounter equal to party level IS normally pretty easy. It's been that way since at least 3rd edition (I didn't make any encounters in 2nd). The party should be able to cut through them and keep going. After something like 5 of them, they will get a bit low on surges and think about resting.
If you want harder fights, even "challenging," then yes you will want to do Level +1/2/3/4 encounters.
Now when building encounters, you can't just rely on the XP totals working out to make a balanced encounter. You can't just take random monsters and throw them together and expect the right challenge level you're looking for.
Your encounter design is extremely important. What monsters you choose: Their defenses, attack bonuses, what they target (AC/Fort/etc.), and their synergy. Monsters can complement each other frighteningly well, so examine all their abilities and think about them a bit. A bit of bad terrain can impact a fight a lot, if the monsters can benefit from it.
As to your Striker ... that's just way too overgeneralized. Not all strikers target exclusively AC, and pretty much none of them really do target just AC anyway. Barbarians, Avengers, Rogues, Rangers ... all have non-AC attacks, though maybe not so many.
Spellcaster Strikers like Sorcerer and Warlock have mostly Reflex attacks, but some others as well (not AC though).
What you have as a weapon user to combat the usually-higher AC values is the proficiency bonus the weapon grants, as well as the ability to Flank (if you're melee) and otherwise boost your attacks in some way (Rogues can impose Combat Advantage, Barbarians, Fighters and Rangers can get bonuses to hit...). Leader powers often benefit specifically Melee attacks also.
If you are concerned you are missing too often, it's probably the way you built your character, or the way the DM is putting encounters against you, or an utter lack of teamwork from your party (common in new players to 4e coming from earlier versions).
Soldier monsters have high AC. Soldier monsters of higher level than you have REALLY high AC. Hobgoblins (which feature heavily in Red Hand) often have that nasty Phalanx ability that boosts their AC by 2 when they're near each other. Soldier + Higher level + AC boost means the melee AC attackers won't hit very well at all. The DM should be cognizant of that in encounter design -- which is why I mentioned that you should keep in mind monster Defenses in encounter design.
Describe your Striker character in detail, and your party, and I'm 90% sure we can help you hit more. Was it an Avenger with a Brutal weapon? (You mentioned rerolls and rerolling 1s).
As a DM my goal for every encounter is to bring at least one player down to unconcious. Not to kill them, but to use up 4 of their surges at minimum. So that for the 5th fight of the day, everyone is sitting on 2-5 surges, which really makes people cringe.
What I'm trying to get at, is if you think encounters are too easy, do more of them before taking an extended rest. Stretch your resources to the very maximum you can.
As for you not hitting enough, well that's been beaten to death so far. And controllers really shouldn't be doing too much damage with their bursts. Also, you have to keep in mind how often the controller misses. So say its a blast 3 attack, and there are 4 enemies in the blast. If the controller only hits 2 enemies, then thats only a 50% hit rate. Heck, Ive seen a sorcerer miss 5 enemies in a blast with one attack. Then when they hit they do 1-3d6 (roughly) whereas strikers do 1d8+14 or 1d4+2d8+6 damage on a more consistent hit. So its a nice balancing act in my opinion.