I think Miz would be a great Face. Similar to the Rock and rapper Cena, he's so entertaining at being a hateable heel - it's only inevitable he'll be great as a face. He's just got to much charisma and demands too much attention to not succeed.
THAT SAID, someone in a previous post mentioned Mic Foley has a Christmas book coming out Le Mizerables or something. If that's the case, the Miz could very easily be switching to the other side to screw over Mic Foley. Him and Ziggler could be aligned.
HOPEFULLY, the Miz fights his ass off for the faces, doesn't betray Foley and they give him an honest run as a goodie. This could lead to a feud with Ziggler for not wanting him on his team. HEEL Ziggler vs FACE Miz at Mania for the WHC would be ... awesome.