oh i dont think its beyond them changing things around (i mean really at this point we really shouldnt be surprised with drastic changes), but i think for the sake of interpretation and audience's familiarity its best that they keep it at Kings Cross and it looking like it did from the earlier films. also there is special significance to why the setting is Kings Cross, JKR explained it herself-- it represented the crossroads so to speak. Harry was in limbo, a transition point between the land of the living and the afterlife; Kings Cross represents the same thing-- the transition between Harry's life being raised as a Muggle and his introduction to his heritage as a Wizard.

as i've said its an ideal, and from a film making perspective, it makes the most sense (to me anyway) to follow what was in the book. naked bum is not a requirement though, i dont care how willing Radcliffe is to drop his knickers although again from the film's perspective, it would be best to dress Harry in whatever attire he "died" in, just so that the audience understands that he's in limbo.