My first char who is 47 used 2handers and am now playing a dual wielder, and i don't think i've come far enough to acually make dual wielding any good, the impression i have so far is very underwhelming and seems to rely on overwhelming offense where a 2hander is more versatile and dosen't rely on opening menues all the time.
Once you go up in levels you'll start 1 or 2 shotting enemies and if they aren't dead by the first charge attack, they're staggered, that's the nice part about 2handers is the amount you stagger enemies, it's almost garentied.
From my experience so far, i'm taking way,way more damage as a dual wielder than i ever did with my 2hander, you'll get usedto the speed of the weapons eventually but the key to 2handers are power attacks, thing is, you can't move and swing at the same time, so besides blocking you're best bet is to load up on stamina and keep enemies staggerd, if they aren't staggered, bash 'em! The only times it's better to use normal attacks is when you know you haveto block or move quickly, like Dragur Dethlords who refuse to be staggerd py power attacks, better to do a normal swing and then block and repeat, trying to conserve stamina to interupt his power attacks. And on that note, if you do go the 2hand rute, invest in blocking till you can get quick reflexes, makes interupting power attacks real easy.
TL;DR Don't underestimate the awsomeness of the bash, it's a life saver and great defensivly and offensivly, and you don't even haveto equipt a shield/de-equipt your offhand to do it.
Once you are higher level you take far less damage then even 1h+shield since enemies wont touch you.
Also, the dual wield powerattack is an AOE attack, you will kill all enemies standing close to eachother with this attack.
Who needs the powerswing of 2h when Dual wield normal power attack have it inbuilt.
Again, 2h is the way to go as it requires more skills and timing.
Dual wield mid game onwards does redicilous amount of damage and with swords and +35% flurry, you will do 2 dual wield power attacks at the time it takes to do 1 2h power attack.
Now, with dual wield power attacks you swing 4 times, and each swing hits as much as anormal power attack. Add in +50% power attack damage from dual wield.
And you do around 5 times as much damage as 2h when you are dual wielding.
But, you do lack stagger and some tougher enemies can crack you open.
But since you are 1 shotting giants and 2, 3 shotting frost and elder dragons. There is little that will "crack" you open.
However, if you play dual wield with no enchanting and no smithing. Then its a different game, its still powerful but you need to apply more tactics.
I just feel 2h is more Skyrim and feels more "right" if you want to do damage.
I cant stand 1h+shield since it was how you was forced to play in Dark Souls or you would die, die die.
Its very powerful and a way to make melee encounters take time and be easy.