A game ending kill streak is just stupid. So I hope that they do not have one.
However, in the hellish instance that they do have one I think that on objective based games if you call in a nuke and you are losing you still lose it simply ends the game. I think this would motivate those who are nuke hunting to still get out and play the game, help reduce camping and all that.
I vote NO for game ending kill streaks though.