Allowing players to switch quickly between teams, from my experience, can cause problems.
Some call it "Gaming the Game", others call it "Dweebery", and still others call it "Damnable and Downright Cheating".
For 90% of the time and for 90% of the people, having no time limit or a very short one would work out just fine. But, IMO the current time limit PREVENTS more problems than it creates.
BTW, players in the arena one night were polled by HTC. They were asked, "What a good time limit for switching teams might be?". The time limit was decided to be 12 hours. This was decided by the players for the players, and it was good. (Jedi, where art thou?).
I say "Leave it alone, it works fine and lasts a long time!"

Mino