When the Orcs were generously enslaved by humans, they were seen to be a rather quiet, and even peaceful race. So what I propose is not enslaving them like total animals, but what if after Garrosh's demise, humans now occupied all Orc land, to always keep them in line? They would not be put in camps or executed (unless defiant), but would constantly be under the oppression of humanity. When they are needed to fight against a menace like the Legion, then they could be totally freed to assist, and eventually put back under watch when the threat is averted.
All in all, discuss your opinions on this proposition.