As noted before, Flair was the exception to the rule when it came to heels with long title runs. That's what made his match-ups against Rhodes and Sting so big. He'd even won the belt as a face from Harley Race at the first Starcade.
Hogan's only real underdog moment was him going against Andre. After that, Hogan was pretty much a superhero in the ring with his Hulking out and leg drop combo.
whomod said: I generally don't like it when people decide to play by the rules against people who don't play by the rules. It tends to put you immediately at a disadvantage and IMO is a sign of true weakness. This is true both in politics and on the internet."