I think so that the attacker can get a little more equaled out advantage, a 5th army camp at least should be made JUST for dark troops. A lot of people don't even use them just because they take too much dark elixir and it just isn't worth it. But with an army camp only dedicated to them, you would want those extra troops in all battles and they could be used more. Maybe even a 5th army camp. But that may be overboard.
