Piper with Ted Dibiese as a close second. If I could re-book things, I'd rebook Wrestlemania 4 and do away with the big, boring tournament (even Hogan says in his book he thought it was boring.) Just have Dibiese win the belt via a screwjob (instead of Andre) and have him lose it one on one to Savage at WM4 instead of in the finals of a tournament.
As far as there being many guys who could of or should have been world champion but never were, that's what makes the world title special, to know that only the very best (back when the title actually meant something, that is) would ever get it. The guys who never won is because there always just happened to be a better option available. When it wasn't Hogan, it was Savage. When it wasn't Savage, it was Warrior. Etc., etc