Pat Riley can read a stat sheet as well as I can, and will find some way to fill holes with better players than he has got, but the specifics of the Heat rotation has got to be a concern. With the addition of Lebron and Bosh - they are not adding Wade, remember - the Heat are very powerful at the starting and backup 2,3,and 4 positions. Haslem is an excellent backup at PF, and with mix and match lineups, takes some SF minutes as well. Mike Miller provides and excellent backup for Wade and Lebron. The Heat were quite weak at the 3 last year, and average at 4, so Bosh & Lebron are a significant upgrade. Miller is an upgrade over Daequan Cook.
After that it all falls apart. Does it matter? Carlos Arroyo and Mario Chalmers are a below-average PG combination, but they were last year too, and the team won 47 games. At the 5-spot, Joel Anthony was not even an adequate backup, but is their best center. The Heat drafted a center in the second round - I forget his name. I have to think Riley is looking for someone, even a one-dimensional player to put in that slot.
Defense. Bosh seems to be getting called a good defender largely on the basis of being compared to Amare Stoudemire. Faint praise. When that is out of the equation, he is called solid-when-he-wants-to-be. One evaluator said he had never seen 30 minutes of defense from Bosh in any game. But late in a close game, paying attention - probably fine. Dwayne Wade is a gambling defender, and generally makes it work with athleticism when he gets burned. For this he has a reputation as a great defender, because his blocks and steals are high. But that is an overrate - he is above-average. He is 28. That is considered peak ability age in basketball - but that is founded on skill, smarts, and craft in the ascension just as athletic ability starts to come off the peak. There may be enough of a dropoff to bring him back to the average category. Probably not this year, though. At the point, Chalmers is a good defender, Arroyo a poor one. Whoever the Heat get at center, it is unlikely they will get two out of three at defense, rebounding, and putback scoring, and whoever the backup is will be even worse. Think Orlando and Dwight Howard. Think Tim Duncan, Al Jefferson, Joachim Noah. The Heat will be above-average on their best nights defensively, but usually average.
One injury and this team is vulnerable. Missing either Lebron or Wade, this is a 55-win team. Missing Bosh, they still don't win 60. With young, healthy players they might not have one serious injury. Ideally, they are a developing team, learning to play together, which becomes offensively devastating by playoff time, and badgered into focus defensely by Pat Riley to close that vulnerable spot. 63 wins this year, high 60's the year after.