Look, I am not going to defend all of Volume 5 finale. Adam was an absolute dude.
But see attached. Hazel literally played crowd control and held off all of RWBY/JNR and knocked down Qrow and kept trucking through ALL OF IT. You have to respect and recognize him as a competent villain who could nearly wipe the table and stop bitching about his reasons. It's nitpicking and ignoring the bigger picture.
Qrow jobbed because it would be stupid and unfair for him to be competent and the good guys would have won with pure numbers. Blame writing situation, don't treat this as valid development.
Cinder did not revert, she never acted like this in Volumes 1-3. It's consistent with the fact that she's getting more and more unhinged and 'feral', along with her Grimm symbiosis that's she's sporting.
Emerald and Mercury - interesting fighters - fuckin' lol. They are only interesting in terms of their rivalries, and Emerald doesn't even have any yet.
Leo was filler not something to whine so bad about.
Ren nerfed? That's a funny one.
Nora using thunder on Hazel and actually scoring a blow wasn't a nerf.
Ruby is showing PTSD which is coherent with her development since Volume 3.
I like how you complain about the villains jobbing while also complaining how the heroes also jobbed. Hazel sucks and yet he wiped the floor with Ren, Nora and Weiss?
Raven - not dumbest character, I hold that for Adam and his performance.
All and all you're all over the place with your complaints. Volume 5 was a clusterfuck of footnotes and you're nitpicking in pretty much every situation. The only valid disappointments were Mercury with a punch and Adam. Everyone else filled their role pretty easily.