I've never taken the Heat seriously as a contender over the aforementioned period, it's the reason why I'm not really taking into account their Finals' appearances.
This Cavs squad is definitively better than all those Heat teams, regardless of what happens this season. Both Finals' runs for Miami were more capitalizing on gifted opportunities than their actual ability and merit as a team, it's the reason why they've had just as many 1st round exits over that period when fortune didn't fall their way.
All in my opinion, of course.