The Cavaliers-Heat “rivalry” never really was one. It had the potential to be unique because of LeBron James. Because of him, it could have become similar to the late 90's Heat-Knicks rivalry after Pat Riley decided to leave New York and come to Miami. But while LeBron was a Heat, there really was no rivalry because the Cavs at that time were no match against the Big 3 Heat. The Heat’s real rivals at the time were teams like the Celtics, Pacers and Bulls.
Cleveland fans and their owner Dan Gilbert sure hated the Heat and LeBron when he was here, though.