I posted an article on Amare in another thread. The article is essentially about how playing under D'Antoni stunted his development in certain areas of the game including defense, and post play. Here is a quote from it:
While the offense was wildly successful, the reliance on Steve Nash stunted Amare's growth as a player. Nash is so good at creating for others that his teammates rarely have the chance to create for themselves, which is something that many thought Amare was incapable of going into this season. It's no coincidence that, over in Dallas, Dirk Nowitzki did not turn into a superstar until Nash left for Phoenix. In 2003-04, Nash's final year with the Mavericks, Dirk averaged 21.8 per game. The following season he tallied 26.1 points per game, cementing his status as one of the game's premier scorers.
So, a few years under D'Antoni with a team led by Nash, neither rebounding, defense or a low-post game were expected of Amare, yet it was his inability in those three areas that had people most upset with the All-Star.
Which brings us to now. If all it took was two seasons with a coaching staff that cared about defense and rebounding to get Amare to be a complete player, one has to wonder how good he would have been if he had been drafted by a team like the Spurs, where Gregg Popovich not only expects defense and rebounding, but demands it.