As far as I can tell, there's only two kinds of enemies in the game.
Enemies that I can one-shot.
Enemies that can one-shot me.
There appears to be an extreme lack of enemies between those two extremes.
This is something I have noticed as well, or well until I turned things up to Master setting after Expert got dull - now every encounter is all of a sudden very lethal again.
But on a note regarding difficulty that I think most here need to know. If you initiate combat with an enemy, decide you'll never beat it and so you turn the difficulty down - nothing will actually happen. Difficulty for all I have noticed only works upon spawning or whatever you're supposed to call it. Now I don't know if that applies to Novice as I have never even touched that diff, barely Adept either for that matter but the few times I did change between Expert and Adept inside a dungeon it helped nothing until I left the area and returned. I could be wrong, but this is not based on a one-time thing. Also Master seems to do very little to "bosses" and rarer enemies, while it absolutley beefs up regular adversaries.
Pro-tip: Get into a position where you only have to deal with one of them at a time, like a small alley or the like, then block-bash and hit as much as you can while he staggers. You probably won't be able to do this for long, but you can do this once or twice before you need to heal in which case you either use potions or make a sprinting run away to get a heal in. Repeat until you succeed. Also if you can see if the guards or something can't help ya, even a wild wolf if you're out of allies. And if nothing else works, run like a cowardly dragon. Never seen a dragon run? They do when I play.