Just an idea i had recently,
I think it would be nice if there was a way to upvote players for being helpful/ friendly/ etc, it could be done by clicking on the player and clicking a commend button or something. This would help people get reputation for being helpful in chats and in game and could possible lead to getting a chat moderation rank or something along those lines.
However, i don't recommend adding a negative rep system instead as it could be abused, you could perhaps add a in game report system. Or maybe not due to immaturity \_(o.o)_/
None the less i'd like a commendation system just as something to show that I am active in the help chat and other players can trust myself and other people :)