As far as I can tell there are only two reason for a rogue to dual-wield daggers:
1) Roleplaying flavor
2) They can be thrown in a pinch
But other than that, is there any mechanical benefit to daggers over short swords? I seem to remember (perhaps inaccurately) that in an early iteration of Next there was some mechanic that increased the likelihood of getting a hit each turn, which meant a greater chance of proccing Sneak Attack. But I can't see anything like that now.
Nope. But reasons #1 and #2 are both completely legit.
The difference of 1-point of damage, especially given the fact that your Sneak Attack damage will only continue to dwarf--by magnitudes--any weapon you choose to swing, isn't worth worrying about.
Daggers are cool. If you think so too, don't be afraid to use 'em. No one is going to take away your D&D Membership Card for doing it.
Daggers are very concealable too, dont forget.
I think the way SA works in 5e that you can play a dagger rogue no problem at all. Even a deadly, pin point accuracy dagger throwing rogue. 
There's one other downside, in my opinion: I really hate rolling d4's. They don't "roll" they just sort of plop. More of a crash, really.
But I may have to suck it up and find my d4's. I just like daggers.
I agree with Carlson.
Sneak attack damage is your bread and butter as a rogue, second only to your sense of style. Daggers have tons of style and don't reek of numbers fetish.
Elfcrusher wrote:
Elfcrusher wrote:
Satyrn wrote:
Well, yeah.
But I was also thinking of a friend who, when he rolls d2 (or d3), ignores results above 2 (or 3) and rerolls
Plus you can carry a ton of them. 
I also agree with Carlson. Being able to throw daggers especially should not be discounted. Between that, the ability to Move + Attack + Move and the extra mobility granted by Cunning Action, Rogues with throwing daggers are probably the most deadly mid-range threat (as they should rarely need to end their turn in melee)
Slightly off topic, my current DM wont let me hide, pop around the corner and get the unseen attacker bonus.
But what would be cool is if I could get it by throwing a dagger! That'd be cool!
Okay, maybe a bit off topic...
Elfcrusher wrote:
Johris wrote:
Personal houserule: daggers can be dual wielded with any non-light mainhand weapon without the Dual Wielder feat. Allows the traditional rapier/longsword and dagger combo that was the most prevalent dual-wield style in real life, and gives daggers a little more play.
Satyrn wrote:
Johris wrote:
3) Sharpshooter feat, dual wielding daggers is the easiest way to double dip on the damage bonus
I have a couple of these big beauties...
I could just write 1 through 4 on it with a permanent marker three times each.
What's more, it's kinda fun to roll big, intimidating dice just to deal only 1-4 damage!
RKVM wrote:
There are plenty of mechanical benefits. See this thread on the Dagger Thrower.
There really needs to be a mechanical incentive to have a dagger as your permanent weapon. The rogue should have special mechanics tied to it. 4e actually made daggers mechanically worthwhile. Why can't 5e?
ChrisCarlson wrote:
Synjin wrote:
ChrisCarlson wrote:
You can throw two daggers a turn using the two-weaponfighting rules. As far as I can tell this is the only way for a single classed rogue to get two ranged attacks without taking the crossbow expert feat. This lets you instead take the skulker feat. This lets a dagger rogue make two ranged attacks per turn while still enjoying the benefits of the skulker feat. Which lets you stay hidden even if your first attack misses.
In other words, a hidden rogue with the skulker feat using daggers gets advantage on their first attack roll. If that attack misses they get advantage on their second attack roll too. This gives them a lot more dice to insure they sneak attack without relying on attacking an enemy within 5' of a party member.
By comparison, a hidden crossbow expert rogue that misses with their first attack is no longer hidden, loses advantage, and is forced to either attack an enemy within 5' of a party member, or miss out on sneak attack dice that turn.
Satyrn wrote:
Varisthenes wrote:
My main group is online, so the threat of d4 caltrops is somewhat lessened. LEGOs, on the other hand...
I think daggers are the only simple, light finesse weapon in the PHB. So for classes that are limited to simple weapons, it's their only dual wielding finesse weapon choice.
I houserule that you can use a dagger and any one-handed weapon for two weapon fighting. Statistically it's the same: 2d6 vs 1d4 + 1d8. If you want you can say you'd be using a special dagger like a main gauche which doesn't have the thrown property to make it mechanically exactly the same.
Daggers are also better than a longbow as long as you don't have more than one extra attack for short ranged attacks.
Samrin wrote:
DDiceRC wrote:
Lawolf wrote:
Noon wrote:
Azzy1974 wrote:
Elfcrusher wrote:
Lawolf wrote:
Elfcrusher wrote: