Over at Kh-vids.net, someone had asked which Organization members we felt the sorriest for. Most people said Axel(gee, I wonder why), and I was a bit nauseated at the amount of Zexion and Vexen answers. Sheesh. Anyway, here was my answer:
Demyx. He was a musician, and you'd need a "Heart" to be effective at it. Even if he still felt(he's said to be the most emotional Nobody, next to Axel), he wasn't complete and it would have made things difficult for him and his music. He was surrounded by malicious people, many of whom were probably his enemies, and he's never shown to be anywhere near as cruel as the others. He could easily have been one of the most complex/important characters in the game, but he's shafted.
As for Axel, it's damned near impossible to feel any sympathy for him because he's largely unsympathetic, and it's even hard to care about his friendship with Roxas or what he wants. One of the posters pretty much had the right idea in that he wouldn't want sympathy anyway. He neither needs it nor deserves it. Whatever the case, given his actions, he brought his own problems on himself, so it's pretty difficult to care about his "pain".
And that's pretty much it. At least for now.