About the new chat layout...

Yes, one more but in the sea of several "I dun like it, revert nauw!" posts I want to give my constructive feedback.

Spacing
  I like to have the ability to change spacing and it being more compact now. It's just a thing that bothered me since I started using Discord. Also, customization is all. New features are great when you can adjust them to what you like.

Highlight on hovering
  It's obnoxious and I don't see any real reason for it. Maybe it was intended as a visual clue to what the popup at right is related to? Possibly, but it's annoying when scrolling or going forth and back between servers/channels and chat box. I had no issues with the line between posts, maybe make those optional as well (customization is all)? That brings the next point...

Popup at right
  Also obnoxious, I believe most of people don't constantly use the same emoji as reactions over and over, that's just spam, then no reason to make the "recent" or "most used" (whatever those are because they don't reflect neither for me) one click away, disrupting the content below just for sake of saving 1 click. Also, it's even a pain to use those with tiny spacing as one from a post overlaps other posts (maybe this was the reason for the highlight?).
  I would be fine with "Add Reaction" and "More" staying though, previous version was very small but this one is a bit big though (maybe a middle ground between both?).

New message line
 I think it has improved, now the "New Messages" thing doesn't overlap the date if it happens to be on the first message of the day. It's less obnoxious, however it should go away when reaching the most recent post and new messages arrive while there. Also no need for it when new ones arrive on the channel currently focused.

That's all for now. It has improvements, but also weird decisions that need to be more well thought.
I might edit this if I find more points.