Reserve army camp

I was wondering if having a reserve army camp would be a good idea. This would be a place that your troops would go if they get dumped from your army camp, but cannot be used in a battle. Lets say youre all set to do a normal raid in global, and someone requests war troops but your camps are all full, instead of getting rid of troops to make room to fill in request, theyre on standby until you bring them back in normal army camp to be used. Any thoughts?

Overpowered, it's basically a troop bank. Also, there have been threads on this already.