I think Austin has serious neck and back issues. If Vince picked a lighter guy, then maybe. But I think the Rock would be perfect for this.
For all we know, its in a contract he has still. He will appear at WM if asked. Trump is all about loot, the Rock had that angle with his $600 shirts. Etc, Etc. I think it would be genius. Plus, have the Rock win and leave, its not like Umaga feuds, he's just a big hired gun.