Wheeeewwww. Started watching this a few days ago and binged all 3 seasons. My head hurts. This thread is on page 6 btw.
A few thoughts that mostly agree with you all:
Tom is the break-out star. Hilarious and just fantastic all around. I think the showrunners probably fell in love with him like we all did and based on the algos and feedback decided this guy needs a bigger role. His rise could probably be charted with Shiv's descent where they intersect at the end of Season 2. Tom's response to Greg talking about California Pizza Kitchen and then eating Ortolan was the best of the 3 seasons.
If it weren't for Greg's chemistry with Tom, which Tom has to drag out of him most of the time ("You are so hard to riff with! big obstacle to your career!"), Greg would suck. I guess the show is trying to not be ableist or anti-neurodivergent, but I've never met anyone, autistic or otherwise, who was as constantly stilted and weak in every single speaking situation ever. It's weird because he's the anti-Grandpa Ewan who uses 10-dollar Thesauruses words in equally jarring and unrealistic ways to illuminate some sort of disorder.
Roman is a weird character because he's always on. All acidic bite and clever snark, all the time, 24/7. It's exhausting as a viewer. It's like death by chocolate and it just wears you out when you binge the 3 seasons. I'm guessing when you wait week over week it's fine-if-still-unrealistic. I guess you could say the same thing about Tom, but I just think he gives his hilarious dialogue in doses and in patterns and situations that make sense (e.g. not in the board meetings, etc.) that it works better. That said, he has issues and someone mentioned he was probably molested by Lester which makes sense, and that's sad and informs his character study, but what I find interesting is that he isn't a heavy drug user. You'd think he would be based on his careless and impulsive nature (and obvious emotional and psychological issues).
Ken is the worst of the kids for me because it's hard to watch him be emasculated and castrated. Good acting to turn it off most of season 2, but the amount of "right right, yea no, I get it, sure. okay, right. yea. yea. for sure." became annoying. I thought the show abandoned his visible drug use / habit / problem pretty abruptly too. There were times he was needing his "straightener" just to get through the 8 hour work day and then nothing really shown (I guess the implication is he's still a daily abuser?).