I dunno, it works both ways. I did NOT want to like Namine, she waltzed in out of nowhere and completely threw off my feng shui, but in the end she was just too awesome a character not to like. Pull the same stunt, Xion, and you won't be sacrificed to the yaoi fangirls like Kairi.
It also goes with liking Namine, and loving her even more. XDD
Both ways work, I just like the insurance that I won't shut out a character because I'm only opening my eyes to their flaws.
That all just proves even further how amazing Watanabe is. It gives us less of a reason to doubt Xion.