Yeah there's some truth to that. However, I actually think spoelstra holds them back, and that with a better coach like Rick Adelman or phil jackson they could win a title easy with their current cast. Their half-court sets are terrible for the most part and at times excruciating to watch and bogs down to your-turn, my-turn. Watching the game it's obvious that wade and lebron play the way they are accustomed (lots of expended energy, dribbling, isolation, relying on athleticism, etc.) and the other 3 guys on the court and spoelstra are kind of there along for the ride.
I think Riley miscalculated with keeping spoelstra. As constructed, what the Heat need is a coach with some skins on the wall who has the pedigree to push bosh, wade and lebron especially to do things that aren't natural to them, but they are things that would make the game easier and make things more fluid, particularly late in games in the playoffs. Someone who could get them to buy into the concept of late in games for example, running high screen-and-roll action with wade coming off a high lebron screen, with 1 strong-side and 2 weak-side shooters spaced out. That is a simple yet virtually unstoppable play, yet the heat hardly ever run that. My suspicion is that deep down spoelstra would like to and has ideas for the heat offense, but I think he lacks the "cache" to get lebron particularly to buy in on expanding his off-the-ball game. Because the core problem with the heat is that both lebron and wade are essentially the same player (ball-dominant initiators) but there's only 1 ball to share.
If I were Riley I never would have gotten the Big 3 together without getting a highly-credentialed coach. It's like putting crappy, cheap-ass tires on a ferrari, you're not going to maximize performance. A team with Lebron and Wade should never be held to 75 points, that is unacceptable. I would have canned spoelstra and offered Phil $20M/year or hired Adelman the day the Big 3 signed on the dotted line.