Over on another site, marni1971 basically heavily implies GMR's Mickey replacement will, essentially, be highly similar to the new Battle attraction coming to Star Wars Land (i.e. Ratatouille/Mystic Manor-ish).
I hope it's more on the Mystic Manor side of things, with lots of AAs, simpler animated figures, and sets, because if we're going to be losing The Great Movie Ride - a fantastic animatronics showcase - for a ride that's mostly screens, and which is a close relative of the other major E-ticket DHS has coming (perhaps even in the same year)... I won't be thrilled.