You know, you really should have to gimp yourself for enemies to be hard.
A tad frustrating
Not after 60-70hrs they shouldn't be.
The game can't be designed for masochists.
I mean, yes one or two or groups should be a challenge, but if a frost troll is going to be a real threat at level 32, then it will be 100% impossible at lower levels and that is just not fun.
The only other way to do it, is to have the enemies level with you and that is equally not fun. I would like SOME sense of achievement when I play a game. If not achievement then at least a sense of progression.