Hey Audo you remember that one time you mentioned that maybe the reason Namine is worried and reluctant for Sora to become whole again is because Roxas joining him would hurt Xion (thus why 'she can't endure it') and not really anything to do with Xion and Sora? I'm starting to think you may have been on to something.
We heard at the end of the one trailer Xion talking all funny to Roxas, you know, the "how do I look to Roxas" bit. If Xion changed appearances, for circumstance sake, say she looked like Aqua, isn't it likely she would be speaking to the Ven inside Roxas, thus the odd wording 'to Roxas'.
What with Xion's strange beginnings and the implication of Aqua's existence with her armor in the Room of Sleep, it seems to me that the two, that is Xion and Aqua, will be more heavily connected then what we can piece together right now.
Besides, if thats the case, it introduces the BBS characters and sets it up to release after Days so people have gained interest.
Lol, long story short, I don't think you should be worried so much about Xion's connection to Sora, I think her connections to Aqua are more likely.