I know you can sneak attack almost anything with one hit, but I mean playing as a character who prefers the lightning speed of daggers to dispatch foes. Not much sneaking.

Light armor
dual daggers (smithed and enchanted or bound dagger - DB)
possibly some archery and a little conjuration

Is this a viable playstyle, or would you get your azz handed to you at high levels?

EDIT: A build like this: http://skyrimcalculator.com/#242377

And again, sneaking would be limited to maybe one sneak attack per encounter.

It seems viable, I use a Mace in the right hand and a dagger in the left though.

Is there any particular reason you use a dagger, or do you just like it?

If the dagger is smithed then it certainly is. Since smithing adds the same amount of damage reagardless of weapon type it has the biggest effect on fast weapons with lower damage - daggers. The same applies to weapon enchantments.

Using dual attacks, with a dagger in the offhand, allows a person to swing as fast as they would with a dagger. Couple that with Dual Fury, dual attacks are even faster. And throw in some Elemental Fury shouts, and you have yourself a blender. This is why it is better to dual wield with a slow weapon on the main and a faster one on the offhand.

Many have used this style. If sneaking using conjured ones, get illusion perk "quiet casting" so enemies don't hear you. As well you'd get muffle and invisibility. But for combat the only issue is a little shorter reach than swords. I personally tried fighting with daggers and it's quite satisfactory.

Yeah, even with sword I had a hard time connecting with each hit int he combo, I wonder if I would be able to hit with daggers. Hmmm.....

The weapons in your left hand determines the speed of a dual wielding attack. Since Daggers are the fastest, I use them on the left hand. Maces do the most damage so I put it on the right hand.

I have a character that dual wields matching enchanted daggers, it is very effective!

I have 778 Backstabs,most of them,I did while wielding/dual-wielding daggers,So,I recommend you use,fast,Regular Damage,with a good enchantment(absorb health,paralyze)And that sneaking perk that Multiplies the Sneaking damage while wearing daggers by 16x,you can almost 1 hit kill a dragon depending on the difficulty