REGISTER TO REMOVE ADS
Despite the fact that the two are connected, Xion has already proven that she's more important than the plot device known as Kairi.
"The one who was thrown in to make the story interesting"
"The One Who Looks Suspiciously Like the Melodious Nocturne's Girlfriend"
I would expect Xion to receive a title; she is an official member as far as we know. Sure, she's different, but then again, so was Roxas. But who knows what they'll do with her?
The story was plenty interesting. It didn't need Xion.