Adding any emoji as a reaction remains under review.
I am marking this as partially done to let you know a new reactions bar with Like, Heart, Laugh, Surprised, Sad, and Angry has begun rolling out to all users.Mateusz commented
Why only one reaction is allowed on single message?
The ability to turn off emojis is still being worked upon.
Also, there is work to create a compact mode which will also help reduce white space… which in turn will impact some of the complaints are far as wasted space from the emojis as well, that have been voiced in the comments.
Stay tuned for more details.
This item is still on the backlog.