Which raises the question: Where do they fit among the most dominant teams in NBA history? The answer to the question, honestly, is that they are just outside looking in.
It would be tough to make a case that they are among the most dominant teams ever right now. Depending on how you define "dominance," you could make a case for the top 20, but top 10 is a reach.
Their current .788 winning percentage is tied with Oklahoma City for the best in the NBA right now, but it's only tied for 18th all-time.
Perhaps the better way of measuring dominance is margin of victory (MOV). In that regard, it's Chicago, not Miami, presently leading the NBA with the eighth-best in NBA history: 9.46 points. Miami is 13th with 9.41.
You could take a look at SRS (simple rating system), which adjusts MOV based on a team's strength of schedule. In that regard, Miami does stand alone this year, but they are only 23rd all-time.
In short, there's not much you can do to qualify that the Heat are one of the most dominant teams. They are in the neighborhood with half a season to go, though, and if they continue to play the way they have been, they can move into the conversation.
Here are the seven most dominant teams in NBA history, and how Miami compares to them and is different from them.