I tend to view Amare's situation like that of a pitcher with a super fast ball who gets injured. Some great power pitchers never regain their effectiveness, but most simply stop trying to blow the ball by every batter. They learn about control, location, movement, and varying the speed. When the fast ball is used, it is a lot more effective because the batter has a lot more to worry about.
An example might be Karl Malone. Obviously Malone's rebounding and defense was better than Amare's, but offensively there are similarities down to the pick and roll. At his peak, Malone was never the jump athlete Amare has been and near the end of his career Malone clearly lost a step. But until his year with the Lakers, Malone did not have year where he averaged under 20 ppg after his rookie season with a career average of 25 ppg.
I would be diappointed if Amare only returned to the physical capability of Karl Malone, but he could still be a Hall of Fame level player.