But, this is what I'm trying to get across. In the beginning of KH, Riku submitted to the darkness. If you submitted to it, let it take you and you not take it, as Riku does in CoM, then that would be a sign of a weak heart. Hence why one who submits to darkness is not worthy of holding the keyblade. To me, that made perfect sense as an explanation.
Submitting to anything is proof of a weak Heart. As it shows, properly controlling the Darkness is sign of a ridiculously
strong Heart.
In Hollow Bastion, as you pointed out, Riku took the keyblade, because his heart was stronger at that point than Sora's, regardless of being covered in darkness. I don't know why that happened, because it goes against what MX said, and what you're saying, though I know it is true, would mean the quote wasn't true, not without an explanation, which is something I would think you, Rain, would be able to give. Sorry for not being as smart as you.
Who the fuck ever said MX was right, or that he was being honest? It could've been his own point of view, for all we know, and thus far, that seems to be the case.
Remember what Nomura said about Keyblade Masters - they're not there to teach skills or abilities, they're there to teach
spirit. Consider this a part of MX's "spirit" - his beliefs. He thinks that anyone that deals with Darkness isn't worthy of wielding the Keyblade, but much like Terra said - this power, he wields for his friends. This ties in with both Sora and Riku who despite having quite a bit of Darkness inside them (as Sora himself attested to at the end of KH2 - the Darkness got to him too) still wield their Keyblades with sufficient and up skills.
But, to me, it would make sense as to why if Terra became Xehanort he wouldn't be able to wield, because he did exactly what MX said woud prevent him from wielding.
Seeing how Darkness has no effect over wielding a Keyblade, I'd sooner explain it with Xehanort lacking any and all Memories of his time before being found by AtW. Roxas himself was unable to wield the Keyblade in the virtual Twilight Town until his Memories of wielding returned, via help from Namine, and he had to go through a whole new Awakening.
Xehanort lacking any and all Memories of his 'past' seems like a likely explanation for him not having a Keyblade despite obviously having Wielding abilities - otherwise we can't explain how he opened the Door to the Heart of Radiant Garden, as well as it's difficult to explain Riku Duel Wielding - if we say he somehow got that extra Keyblade he lent Kairi from Xehanort within him, it all adds up, with Ven's relation to Sora and Roxas as well.
And of course the simple explanation would be that because he's not quite the same person he used to be, most likely, the Wielding ability was somehow 'sealed off'.
Darkness isn't really an issue.
If trying to find a logical explanation to what the thread starter wanted to know is wrong, I'm sorry for ever even trying.
Meh. So long as the debate's going on smoothly and the thread opener doesn't mind I don't really care about straying that much off topic :v just keep it civil.