This is why the game is dying and failing. If the game isn't expecting you to grind something in coop then you're expected to manage your 3 retarded AIs that get killed easily or get stuck doing retarded shit.
Co-op isn't much better than the retarded AIs sadly because everyone is a dick in this game. If you don't meet some retarded might requirement then you're filtered from most rooms and have to find a friend or hope some desperate/lowbie pubs will eventually take you AND clear.
Met the might requirement? Great, now you're expected to fully know the fight, have practiced the fight and make zero mistakes because if you die or play badly then people will quit on your ass. Then repeat it like 100+ times because the game expects you to farm it so the game becomes an extremely tedious chore that isn't fun anymore.
Then you have games like Shironeko where the game is largely single player and the times where you're expected to co-op aren't a chore because 2x, 3x, and 5x drop rate boosts exist and are easy to get on top of people simply not giving a fuck what you play as or do most of the time unless you somehow manage to royally fuck up which makes for a much better and nicer experience.