Dwight is not only the reason why Magic are better. Magic's teamwork is awesome; they don't rely only on Howard. On the other hand, No one can stop Lebron too, but he is the only one they rely on.
Yes, they do rely on Howard.
Due to the fact that Cleveland doesn't have anyone that can handle him in the box one-on-one, they are constantly bringing in someone to double team him down low.
That leaves a perimeter man wide open.
The open man either takes the shot, or waits for another defender to swing to that man, and then the ball goes around the perimeter for an open look from 3 point range.
Orlando's offense is either banging the ball down low with Howard, or 3 point shooting. That's a dangerous way to play.
Why do you think that Orlando is having a seemingly easier time with Cleveland than they did with an injury depleted Celtics squad who absolutely ran out of gas in Game 7 of that series?
One reason. Kendrick Perkins
Kendrick Perkins has been the only player in the playoffs so far that has been able to cause problems for Dwight Howard. He used his strength to consistently knock Howard off the blocks, and played such physical defense that the Celtics didn't need to double him. You noticed that those open looks for Pietrus, Tukoglu, and Lewis were much harder for them to come by against Boston.