First of all I really really really don't remember anybody being "afraid" to step into Amar'es paint. He was a completely undersized center and has never been a great defender.. I think watching some blocks on ESPNs highlights might have you thinking this way..
Second of all even if he WAS a better scorer, which I really think they were about even, you give Chris Bosh Steve Nash and he could have scored that extra 2-3 points per game that Amar'e was averaging over him.. Especially considering how good Bosh would have been on the pick and pop.. I mean Nash even made Channing Frye and Boris Diaw looks good playing that way, imagine how Bosh would have flourished..
But even if Amar'e was a slightly better scorer then he has steadily declined in his level of play.. His 2K rating should reflect that somewhat. His shot attempts have gone up, points gone down, FG% gone down, and he only managed to play in 47 games this past season.. As for Bosh his shot attempts have went down, his FG% has actually been about the same, in fact the year before this past year was one of the highest of his career.. His rebounds and points have had a slight drop but that's arguably due to his touches and shot attempts dropping..