I agree with linear that it would kill the population, since some players have their own preference side and stay with it for the rest of the half and change teams after the swap sides.

I think stacking is not actually a big problem anymore after the implementation of the new improved atb system. However, the atb system could need a few tweaks here and there as sometimes the top fragger in the losing team get switched to the winning team, making it more unbalance.