The problem with teams is a lot of the time, all the good players go on the same team which is lame because it can ruin the game for the rest of the players. This option would set up the teams based by player ranking (i.e. the player with the highest score is #1, player with the second highest score is #2, etc; etc.).
It would basically look at the ranking of the players, then take all the even ranking numbers & put them on 1 team, then the odd ranking numbers on the other.
The biggest problem with this would probably be people would hate to be constantly switching teams, which is something that may happen. So this CVar would probably have a few different options: When set to... 0 = It is off. 1 = Sets the teams every 15 minutes. 2 = Sets the teams every 30 minutes. 3 = Sets the teams on map change.
Setting the teams on map change is probably going to be best but I can already see people disconnecting & reconnecting to not apply to the setting of teams. There are some holes as to how this will work but you should get the base concept of the idea.
This would not only be useful for the TFFA gametype but the Team Duel gametype as well if Lee ever finds the time to add it.