I mean, think about this. Roxas can dual wield because he is the "nobody" of a Keyblade wielder. He fights with Oblivion and Oathkeeper; the representation of Sora's memories of Riku and Kairi. He can feel emotion (apparently) and was formed when Sora became a heartless. Not that when Sora became a heartless, he wasn't normal. He sought out Kairi and was returned back to his former self.
Perhaps Roxas isnt a nobody. Perhaps Keyblade wielders can't develop Nobodies like normal people can. Perhaps Roxas is a failsafe implented if a Keybalde wielder was to fall into darkness...
Perhaps Ventus was somehow saved from his possible freezing death by being merged by the heart to a future Keyblade master?
Oh yeah, I know Ven didnt die instantlyfrom the freezing attack from Master Xehanort, but he may have died later from it.
Perhaps Roxas isnt a nobody. Perhaps Keyblade wielders can't develop Nobodies like normal people can. Perhaps Roxas is a failsafe implented if a Keybalde wielder was to fall into darkness...
Perhaps Ventus was somehow saved from his possible freezing death by being merged by the heart to a future Keyblade master?
Oh yeah, I know Ven didnt die instantlyfrom the freezing attack from Master Xehanort, but he may have died later from it.