I really don't care that the health bar is green, it looks alot more spiffy this way.
However, everyone knows there IS NOT a green team, for the sake of making things simple, at least give the current team your on Green IFF's, the other teams can keep their original colors. There at least should be the option to indicate teammates, and revert to the classic IFF style alltogether.
I wouldn't mind playing with friendly blue IFF's and stuff, but there really needs to be the ability for choice in that matter.