Level is pretty irrelevant, aside from the bonuses you get from stats and feats. Maybe moves, but personally I regret buying the one move that I did buy for Catti so far. I have to go out of my way not to use it because it turned my basic LB melee into a slower kick that now also reduces max stamina.
It's all about gear, and the utterly retarded thing about progression is that you have to have good gear to get good gear. Not great gear, just minor upgrades and sidegrades 99% of the time. From level 8 on I was doing CR5 (2300) because I seeded the character with just enough L4-5 items that I could keep getting more of them. Still no way to get any higher though, so CR6 is completely out of reach. I can kill the trash, but the elites/bosses turn into ridiculous damage sponges, and one hit from anything is instant death.
Seeing more and more things that would really bug me if I had any intention of playing the game long-term. Like the loot system is super basic. Upgrading items gives a small % increase over the base stats; even upgrading it all the way (ungodly expensive for anything past green or blue) still falls well short of just finding a replacement which is +1 item level. You can't modify anything else besides the skin (read: tint), so no swapping stats or anything like that. If you wanted max crit gear you'd have to pray to RNGesus that everything drops at max item level and rolled perfectly.
The UI is rather shit too. There's no 'mark as junk' or any other way to quickly sell loot. You sell each item one at a item by holding down a button for a few seconds. Clearing out a cluttered inventory is tedious as fuck. There doesn't seem to be any alternative to just vendoring shit either. Given the insane amount of crystals you need to upgrade higher tier items I'm rather shocked that there's no way to break items down into crystals. Feels like there will be a point where gold just doesn't really matter anymore so that's a rather glaring omission.
The monsters attack much more frequently on the higher difficulties,
Definitely not seeing this. Half (or more) of the mobs in any given encounter stand there doing nothing, and the rest seem the same as always. Plus any sort of height advantage completely shuts off the AI. It's not even just perching on a cliff, I see it happen a lot when I just back up a slope a little.