Power attacks with two weapons at once hit with both weapons twice; second, first and then both at once.
So that's four hits, possibly enchanted, and the possibility of sneak criticals. Plus poison.
This.
Once you have sufficient stamina to be able to power-attack three-four times without it draining completely, you basically turn into a killing machine if you have proper weapons. Currently I'm wielding Mace of Molag Bal for damage output and soultrap and Dawnbreaker for extra fire damage. I have the perks that boost power attacks (standing AND dual-wielding), the one that reduces its stamina cost and of course the one that increases damage by one-handed weapons. I'm telling you, there are not a lot of opponents that can survive 3+ standing power attacks with both weapons simultaneously.
I have to do without blocking, though that's a sacrifice I'm willing to make, since you can actually dodge enemy blows.
It's good to have an edge over your enemies, mainly on higher difficulties.
My current character is a gentlewoman thief, so of course she dual wields daggers. But I also made it a personal rule to only increase health once every five levels, and magic once every ten.
They're only orcish daggers at this point but a sneaky power attack dual dagger 15x combo monsterkill fatality? the main difficulty with that is the sneaking, not the stabbing. And the dragons, bringing friends and never landing. Dangerous Dragons, Dragon Overhaul and a couple other dragon buffing mods makes thief a scary build in falkreath. But I managed to pass the Thalmor embassy mission without ever being caught by more than one guard at a time, which I consider a stealth mission success.
The problem with that though is that you can get at LEAST that much DPS with any Two Hander, AND those get to block...
I don't need to block and don't usually want to. It's probably a sign of good balance that both builds are viable "DPS" builds, letting me play a thief because I want feel afraid of being caught while allowing you to JUSTICE / WRAAGH bandits with impunity.
That said, can't be sneaky deaky when you're hauling around a Zweihander.
*Enormous scraping noise as dragonborn shears off a groove in the top of the ceiling.*
"Huh, must have been the win- BRUH"
Decapitations are not lady like.