It seems like whenever I'm working my way through a cave I run into only two kinds of enemies: The kind that die in two hits, and the kind that you need to wail on for a couple of minutes while pausing every few seconds to heal yourself. And there is no way to tell which kind that new mob running down the hall will be: it's totally possible that you'll one-shot the guy in heavy plate, while the girl wearing cloth and no shield will take a few dozen hits to kill. What's up with that?

Easy to distinguish between the boss and the lackies.

Mobs? This ain't minecraft. They're bandits.

Anyhow, lesser bandits always wear leather, while marauders and chiefs tend to have full steel plate and a shield often.

Draugr. Oh my GOD Draugr.

Draugr = One hit.
Restless Draugr = One hit.
Draugr Wight = Two hits (barely).
Draugr Scourge = Two hits.
Darugr Overlord = 7-10 hits.
Draugr Deathlord = backpedal ad infinitum.

Just right now Farkas and I spent a good long while hacking at some girl wearing hide armor. Her friend in iron went down pretty easy though.

Not the rule, the exception.

I agree with the OP. While I admit I have just barely scratched the surface of the game with dozens of hours, what I've seen so far is that there is a huge difference in the power of the enemies.

The "typical" enemy, like Bandit or Skeleton or Wolf, extremely easy. However, I higher leveled enemy of the same type can be amazingly difficult. There seems to be too much (ie unrealistic) variation between the normal enemies and the "bosses", in my opinion.

I find plenty in between enemies.

They followed the 4e D&D model and made minions, elites, and solo monsters.

Not really, but that is kind of the effect. I actually like it that there are plenty of mobs out there that my fireball will wreck the whole group of, while in other fights I have to work for it. It gives a decent boss fight feel.

My issues are the mobs are not nearly aggressive enough, I hate how I'll shoot them they will stand there for a second doing nothing, get shot again raise their sword an shake it a bit, if I am found they will come towards me pause a couple times along the way to look intimidating, before finally approaching me hell and even during the attack sequence they will waste time to look threatening.

I want them to get shot and instantly charge to the area they were shot from, you would think you would be able to figure that part out, once closer sure pause to find the guy, the charge and attack as fast as they can only stopping to block or otherwise defend/heal themselves, with the occasional power attack thrown in. Oh and intelligent foes should cast detect life if they don't see ma within a couple seconds.