It becomes a very interesting decision for Facey long term. If he accepts (as many others seem to) that he will never make it into the main Manchester City squad is he interested in staying with us permanently ? If he likes the city and we're willing to pay him well would we be a more attractive option than say Aston Villa or Crystal Palace?
It'll probably be an earnings decision for him. Even if he can't make Manchester's first team, he could still force his way to a smaller club and earn as much or more per year than he could in MLS. For that reason, I still think it will be a challenge to hang onto him long term. He's going to want to try to stick somewhere in Europe.
FYI, his contract with MCFC expires in June next year. If I were him, next spring I'd ask for a short term loan somewhere in England as an audition. If he doesn't get any looks next summer transfer window, maybe he makes New York his permanent home.