I've never bought this theory simply based on how the WWF Champ was booked in the 80's. Heel Champs didn't get much if any time with the title, and ending a WrestleMania with a heel winning the title just seems so..."anti-wrestlemania" in that time frame, so to speak.
I think the plan was simply executed as it was laid out...Savage comes out with the belt, Hogan endorses his title reign, and Savage runs with it until the next WrestleMania, where Hogan could re-assume his place on top as Champ.
I've never really seriously thought any other ending was in play, to be honest.
Same here. I never bought the theory that Dibiase was the planned champ coming out of WM IV.