RNG wasn't the problem for me in D:OS, the problem as I can pinpoint it was :

Yeah, most of the loot was lame. It was mostly linked to the fact that there's "only" 20 levels in the game, so basically, if you find 1000 items in the game, you have 50 items at the same level, so for a sword for example, basically at the same level you're bound to find 50 times the same sword. The problem was mostly the stats given by items on top of the base. A lot of those stuff were just pretty useless, you got a +1 in an attribute that could interest you, and the rest was mostly meh. Some magic resistances here and there and that was it.

There was also the fact that, for example for sword, every crafted sword was better than what you could find, and when I say better, i have a sword with 60-100 damage, and i'm still finding 35-60 damage swords... So yeah, everything I find is junk. Even the uniques I'm finding are useless.

I don't know that RNG is bad, I do know this though for D:OS EE :
Too few difference in certain items (there could be +1 in every skill in the game, that's not the case).
Items that give a competence are lame (if it's not a skill from a school you master, they are useless, so the item itself is useless).

The problem with RNG will always be the fact that there are so few level. If there was as more levels for a character, the loot would be less dramatic I think. (I'm not suggesting the leveling system should be changed though)