Player Re-Entry
If a player joins a server and gets punted to spectator they can never re-enter the match until next race. This is an issue because if the admin is connected and afk on track (the admin kart cant be punted to afk spectate automatically) then the other player who afk'd (presumably on accident) can never connect and advance the server by racing.
Also, As is my habit to suggest a feature on top of a bug, it would be nice if the admin could allow players to join at any time, no matter what even late into a race. This would have been a godsend when running the game at the PGX convention since many children who wanted to try the game didn't understand having to wait until the next match.