Back 4 Blood, opinions
What makes Left 4 Dead work is clear level design that always funnel you towards your goal, and make it clear how to reach it - you prepare in the safe room, you roll out and steamroll your way towards the next safe room, and then you repeat it again for four levels.
In Back 4 Blood there's so much mechanism bloat pushed in just to differentiate it from Left 4 Dead, you start in the safe room, you have cards that change how things play out, you have way too many weapons, some are in the shop, a lot are out in the world, they have attachments, maps suddenly start having subobjectives, it's just a mess!
Back 4 Blood, opinions
But the single biggest crime, is that it's a zombie shooter where shooting zombies aren't satisfying. In Left 4 Dead 2 your shots would tear off parts, gore going everywhere, but in Back 4 Blood it's just, meh, they kinda fall down limp after a few shots