I don't ever think there should be a way to sabotage your own team in core. Say some troll is on a really good team, a suicides to get an emp, then the team has a pave low, is in the process of calling in juggernaut armour, and has an assault drone on the ground. I don't think there should be a way to sabotage.
I think EMP is pretty well balanced as it is. One thing that is frustrating is that if you get a good killstreak you want to put toward challenges, and then someone detonates an EMP right before the end of the game. I'd like to see maybe half of a challenge done when you are left with a killstreak at the end of the game.
