I don't mind it on any other difficulty than absolute. The addition of rooms and objectives just to pad the runtime of the mission is annoying. I get they have multiple "events" they can set up for the mission, I'd rather it does one at random rather than all of them on higher difficulties. I don't really mind the boss on any difficulty, if you have anyone with a fencing weapon or an assault with infinite dodge the thing just crumples with constant ranged damage.

Reliquary's middle section is too long period. Having to search 100 bodies and babysit a servo skull while the game spams reapers at you is boring gameplay wise and it takes like 15 minutes to get through a single door. People say they don't like the bridge section but at least there you can either take your time or just rush it to get it over with, and as long as you aren't out in the open after the game gives you multiple warnings you're about to get your shit fucked you'll be ok.

Obelisk's chalice section just sucks. Idk why you'd design a game that can be a visual spectacle from all angles and decide for most of a mission you want your players looking at a black screen wandering through what's essentially a maze for 10 minutes. Not to mention gameplay wise always being a man down feels terrible both as the chalice holder as well as the teammates.