And how do you know that exactly? The only time, as far as I know, that Warren has talked about the artwork was way back at GDC 07 when he was on GFW Radio, where he said the opposite. He showed high-up Disney execs artwork he himself deemed as to far-out and extreme, but the execs went along with it. And the zombie Goofy from the artwork is still present, judging from the Donald zombie ingame model:
So it's not like they have scaled back on what they have had in their minds when coming up with the concept. There is still the animatronic versions of all Mickeys friends and the messed up forgotten Disney characters like the Hades-Beetleworx enemy we have seen.