I've been thinking about this exact thing, I feel like this would be a good addition because it would add a level of depth and strategy to the game that i feel like it needs. In its current state you have nothing to lose or nothing even really to think about when placing down a power other than where to put it down and the event that you might miss. Say if your army is facing off against another army and they start glassing you, you might have to just cut your loses and push straight into their army so the other person has to stop glassing in fear of hitting their own army or making a 600 iq play as shipmaster by displacing an atriox player's army into their own eradication, stuff like that, cool new ways to approach a conflict and use some powers to make other players powers be used against themselves.
I support this, it was fun messing around with powers in 1, but I didn't really feel it that much, cuz I played Arby, back then. It's return would be nice, as every leader has an offensive power, and it could be an indirect Nerf to GB, as you can no longer throw it out with no worries, satisfying those wanting it to be nerfed to some degree. (Also, I play Ship, and the possibility of using my opponents powers against them excites me.) But I would add being able to use your buff powers on teammates as well, to further enforce teamwork. Imagine chilling at your base, unknowing of anything around you, and you get enemy Vultures teleported to your base to punish you for ignorance.