If X-men Apocolypse gets created (most likely without Singer attached as if they fast track it), having future spin-off's be part of the horsemen would be a great idea. They could also include the other Horsemen as those whom become the members of X-force...instant spin-off potential.
I really do not think Channing will do a bad job at all. He has done the street tough role, the charmer role, the straight up action role. The actor has love for the character, even before knowing a movie was possible.
Give him a chance, I think he could pull it off.
Until there is actually a confirmation HE has signed on though, not just the producers moist dream for the role, we can hold off on the hate or the love for that matter.