To point one thing out, Amar'e has already had a huge injury, and he recovered from that better than anyone could ever have imagined. I wouldn't be too worried about him in that regards. On first thought, I would at least contemplate the thought of it. He is a scoring machine and has a better offensive game then what Lost here wants to give him credit for. He's a much better outside shooter than Drew is at this point, and he's tough to stop when he explodes to the hoop. He doesn't have much of a back to the basket game, but he doesn't really need one with how athletic he is. However, he's a terrible defender and despite how much I like his offensive game (to an extent), he also relies far too much on the P&R to be effective. I'm also not sure how quickly he would adapt to the triangle or how willing he would be to share touches with Odom, Gasol and Kobe. So, in the end, even if we could get rid of Sasha, I wouldn't do it. Bynum has such a high ceiling and really fits our team well for what we ask of him (mostly). Stoudemire wouldn't. At all.
He is way better on offense than Bynum, but he is a huge ass on our chemistry and awful on defense. Remember he wants to be "The Man" on his team, and that'll neve happen with Kobe there.