it was Wrestlemania and IMO the World title match should ALWAYS go on last.
Take Wrestlemania 19 the following year for example, you had big matches like Hogan / McMahon and Austin / Rock, and Vince was awesome enough to let the WWE Championship match go on last.
If a really hyped match should go on last, any other PPV except the Rumble would be fine. I mean if that was the case, Goldberg / Lesnar would have been our WM XX main event.