I don't understand your point. Getting kicked for being idle isn't anything new, there will be literally zero controversy. Kicking those who have been in spectator for a while honestly has no downsides imo; it doesn't effect balance at all.
Being able to create a vote to scramble teams could help bring a little more balance to the server; Whether the players just feel like it or one team is dominating the other for an extended period of time.
Don't see any reason why it shouldn't be added :) Obviously it should be implemented...
Like I said, removing them from blue alone would be more ideal.
Blues get 1.5x damage and reds get crits, that seems fair to me; Blu remains generally stronger but reds still have decent chances at killing a blue and rebelling.