Make it so that you can report a person after leaving the post-game lobby
Oftentimes someone is extremely toxic in the early-mid game, so i mute them and when the game ends 15+ minutes later, i've forgotten about the person (since it was a while ago that i muted them and couldn't see their chat for a long time) and leave without reporting them, then i remember a few minutes later (or maybe like a half second after i click "Play again") and there's no way to report them now.
You should be able to go into your match history and have a report button somewhere on the person's rectangle-of-info thing to report them.
Would help for the people who mute others a lot and often forget about toxic players.