I suspect that this will be a problem all year, even if Amare learns to block out. One of the problems with being a running team is that you can't run with five guys in the paint trying to get the defensive rebound. At the same time, teams that send everybody to the boards like the Hawks did will get some points but give up a lot more at the other end.
Defensive oriented teams usually are more concerned with getting back than in crashing the offensive boards. I don't have access to the stats any more, but if memory serves the teams with the best offensive rebounding stats typically had the worst defensive statistics.
That being said, the Suns players will have to rise to the challenge because they do not have a reputation for being good rebounders which encourages opponents to crash the boards.