Anyway I tried this mod on a vanilla game with a high-level character, what I mean is no other combat-related mods of any kind, and I really enjoy it! Cannot recommend it too much.
**folksy chit chat (below)
This mod changes a couple of perceptions, one of which is that you're immortal. You're not.
You die more easily when's there's more than one opponent (which is good, makes sense).
Plus you still deal great damage & everything, but... you just have to be more careful. Which is good!
Now my own opinion, Duel Combat Realism tilts things a little back more toward heavy armor and two-handed, y'know?
Which makes sense too, because why would you ever want to lug all this heavy stuff around anyway, all over the place?
So it's good. Realism.

Tough to be a mage, baby...
**
so I was going into a cave, it was a bad Falmer situation where they had drilled into a tavern, you know that one?
Anyway it was a very bad situation and they were very lethal.
I noticed that there were seven, including chaurus I guess, but they all lit up red and they start coming for you.
Right down your throat, they start (they're coming) heheh...
They ignore Serana, and her summons, and my Daedric Lord, and come for me!
We had our hands full - and I died repeatedly. Fun.
So it's gonna be like this eh Duel Combat Realism?