I try to avoid this question because it's a bit painful to admit in advance that a game I've been looking forward to for so long is probably not going to exceed expectations, but as of now KH3 is looking like a solid third or fourth place after Days, KH1, and CoM. I guess if it was broken down into its various components it might win me over in some areas vs others (like gameplay vs plot or vice versa), but as of now my general feeling is that it's going to be an experience I will open myself to and try my best to get as much out of it as it offers, but I'm ready to see it as a bit of a let down all the same.
I don't think it will be an especially bad game, though. I don't think it'll be DDD. I think it has sufficiently insulated itself with story material and predisposed character work that it's unlikely to be truly unsatisfying: I think there will be something for everyone in it, and that's about where I'm harboring my expectations. Something that makes its emotional case to the best of its ability, even while it doesn't match the narrative achievements of its predecessors.
Of course, a lot of this hinges on how many risks the game is willing to take. Right now I see it playing things very safe in terms of everything from world choice (new! popular! easy!) to gameplay (lotsa stuff! big! flashy!) so if it can reestablish that balance of a conventional pop culture framework married to a sort of subversive elaboration of its core themes beyond their most familiar elements, there's room for it to surprise me. KH will probably never make it all the way to being topical, but at least internally its best installments are carried by a cleverness about the exaggerated reality of its own premise, while the worst wield it carelessly at face value. I'd like to see KH3 fall somewhere closer to the former trend: live up to the spirit of KH1's central "that's just wild enough to work!" mantra.