What I don't understand here is... Why are we changing the UX here at the same time that we are experimenting with allowing longer-form comments?
UX changes are always going to get blowback and negative feedback because either they break someone's workflow, make information someone thinks is more important harder to access, or people just don't like the new look and think it's crowded. But the whole point of what you're doing here doesn't even need a UX change, you could have experimented with expanding the content allowed in comments without moving to this new UX at all.
These several initiatives did not need to be combined and likely would have been received/responded to better if they weren't. You could have simply replaced the commenting editor with the stacks editor, increased the allowed length, then when displaying comments implement a "show more" button that becomes available when a comment takes up more than a set height. The curation buttons didn't need to move, we didn't need a new vote button, we didn't need more whitespace, we didn't need strictly need threaded functionality (but that too could be tested without the UX update,) it just feels like you're trying to do too much.
