Here are my three:
1. QTE with RNG
I did a quick scroll/scan of this thread and didn't see much talk about QTE, sorry if I'm repeating someone. But specifically, the type of QTE that I think is pure bullshit is when the prompts are different each time you try it. It's especially galling when there is little QTE in the rest of the game. For example I am thinking of the older God of War games boss fights where, IIRC, you used the standard gameplay mechanics to whittle them down and then to advance to the next phase of the fights or finish them off you have to do QTE to execute cinematic moves. But each time, the prompts are different so it's like Simon Says in the middle of my action fighting game and it's like, yo, wtf right now. I think the Kayran (sp?) fight in Witcher 2 was like that, man that is some bullshit.
2. Useless skill trees
I know people like skill trees and building their character. But games that aren't RPG's don't need them, it is just noise.
I am a huge Assassins Creed fan (yes, I acknowledge and agree with all the criticisms, but I still have fun with them, whatever). It will never nor should be an actual RPG. But with "RPG elements" (ugh, shit or get off the pot, either do a thing or don't, stop with this "elements" crap) they have skill trees now. But in order to make the game accessible to its target wide audience, you can get all the skills, or it doesn't matter what you pick you're still dodging and attacking. Valhalla's skill tree was deservedly mocked for having like 400 dots that all do nothing.
3. Useless loot
Similar to #2- a loot system should have value, not just be a way to collect 1,000 broken swords or whatever.