When UC was around it had an awesome mod (I don't know the name of it):

When you were at the pick team screen and you chose a team that was full at the moment, it would automatically put you on the opposite team.

As opposed to how it is now, where it simply tells you that the team is full, in which case you could repeatedly spam the number 1 or 2 button in order to get on the team you wanted, eventually. Also, with the mod in place you can't simply switch teams after a couple rounds have been played. There must be settings within the mod governing all this.

It's really worth exploring, especially now, because of all the team stacking and map stacking, and the associated complaints.