while useful, they are still the downfall of "campers" which i dont see the problem with, it is a legit strategy unlike hacking so while useful it still harms players playing fairly. But as for no time, it can be set up like recent Call of Duty games where the kill cam pops up but you have the option to watch it or respawn.
I don't see how you can think there's time - when you 'die' you get downed a la Gears of War (as for whether you can be finished off or not I haven't a clue, but that's irrelevant), and you wait around for medic to come pick you up. In addition, the ability 'Downed Fire' which, as its name suggests, allows you shoot while downed, would probably not even be worth using if it meant either forfeiting killcams or a moderate delay between being downed and being able to retaliate against your attacker.