Mods should not be curators of good and bad content. Their job should be removing blatant spam/offensive content. I do not want a small, private group of users shadow banning comments or massively upvoting posts.
A warning system is probably worth having though :shrug-outta-hecks: I thought removing comments already kinda functioned this way, but I don't think it alerts the user what was removed. That's the only change I think should be made.
I haven't seen that issue here, broadly speaking.
Some of what you suggest is very subtle, and many people wouldn't notice it being done to other users. It seems like a very direct, but subtle, way for moderators to pick sides and show users they like/don't like different treatment. With removing comments, it is obvious to everyone a comment was removed and checking to make sure the decision was fair is easy. Collapsing a comment because you don't think its great is subtle enough for other users not to notice, and is a very subjective ruling.
Giving them subtle tools is what encourages power. Right now, if a mod doesn't like what I post, they have to justify the removal. They don't have to justify collapsing because "oh it was just low effort" or something like that. With a removal, the reason needs to be concrete and defensible. Which is good, that's the role I feel moderators should have. Remove things for clearly defined reasons.