An element of Nexuiz that really needs work is team balance. What little there is now is worse than none at all. I have no idea how many times I've been on a team that is being solidly thumped by the other team, and then being told by the server that one of our players have to join the winning team.
I think the team balance could be improved like this:
1. The server keeps track of the player scores between games — not online sessions, games (or maybe this should be done by the client?). When a new level is loaded, the players are distributed by their scores from the previous game. That way the teams get and equal share of the best players, the mediocre players, and the poor players.
2. The server keeps track not only of the scores of the teams and the players, but also of the rate at which the team scores are changing. That way, the server will know if the losing team is gaining on the winner or not. This can be done simply by comparing the current score with the score at the last time a player joined or left the game. The point of this is to make it easier to adjust the teams so that the scores will be as equal as possible when the game ends.
3. New joiners are automatically placed in the team that is having the most trouble. Note that even if a team is in the lead, it will get pounded if the other team is gaining at a ludicrous rate (see #2).
Team balance is something that really needs work. Seriously.