I would work for that man again in a heart beat. Because for as much as he was apt to yell, or dress me down, he was also willing to give good advice, to elevate, to teach.
The office is not a safe space. You seem to know what's wrong, IM sure you have asked nicely. I am sure you offered the carrot, but does your team know you have a stick?
> The same people leave detailed comments on others' merge requests
Call these people out, in public, for doing good work. Tell everyone they are setting the bar and others are not living up to it.
> People blindly accept suggestions
Coaching, lots of one on one coaching about finding and having a voice. Lots of "team building" where you level out the playing field with the strong vs weak voices. Figure out what those quiet ones excel at and do a fun activity around that. Let them find legs...
> People send their MRs to side channels or other teams
Stick. Harshly worded emails. Down dressing in public. Telling your team that in no uncertain terms that "this is unacceptable behavior"
As for the chair thrower... He was always fair, he always had his team first, I grew as a person, a manager and an engineer working for him. Its not growing happy go lucky good times while I get a pay check, its Growing pains, spreading that (pain) around is part of your job.