Read this first, its straight out of the TESwiki:
The following are the perks that become available to select as the skill is leveled up, (X=determined by rank):
Hack and Slash - Attacks with war axes causes extra bleeding damage - 3 ranks
One-Handed Prowess - One-Handed weapons


One-Handed Tactics - Unknown effect
Bone Breaker - Unknown effect - 3 ranks
more chance to have a critical hit with swords
Note: Not a complete list.
Note: A multi-rank perk's skill requirements vary depending on current rank of the perk
Alright, if you didnt catch what i'm trying to point out there, i'm sorry. Moving on...
this being said, you gata specialize to even get the perk to deal sneak attack damage with the dagger (which i find is insane). Other then that, this means they will be ETERNALLY FEEBLE compared to other weapons in game.
I, for one, would think dual wielding daggers would be a very typical and classic choice for rogue characters. But if this basically means your going to be just god aweful in a fight, i cant imagine why you'd do it! Sure, you'd get a beast ol WTF BANG as your opening move, but then if any amount of combat ensued after the fact, you'd be screwed because your weapons would be super feeble late game, compared to if you were just using swords. In fact, i dont even think you'd want to use daggers for stealth!
Heres some math to support my case.
1h weapons deal 6x damage
daggers deal 15x damage (top teir perk btw)
5 ranks of one hand prowess = 2x base weapon damage
that being said, were gana be generous with the numbers.
Longsword (confirmed in a pic) deals 9 damage
9x2=18x6= 108
Since we dont know, lets say a dagger deals more than 6 damage. Sounds reasonable.
6x15= 90 (-18 damage)
7*15=105 (still -3 damage)
8x15 = 120 (finally +12 damage)
In the end, the numbers are STILL negligible. at 1 less damage, its not even a hole strike worth in difference, for still doing a ton less damage in combat!
TL;DR
Since these forums are notorious for not reading, lets just sum it up. Really though it only takes like 3 mins to read...
Daggers dont benefit from damage increasing skills! This will undeniably make them sub standard in combat to dual wield them. Their advantage (stealth damage) can be done equally as well with just 1. Even with that being said, if you max out the damage buff perk, swords can deal almost as much sneak attack damage as a dagger!!!
The end result is that your sneak attacks arnt much, IF AT ALL, better than a sword. On top of that, your combat damage is absolutely pathetic in comparison.
Is there something i'm missing here, or is this pretty much spot on?