Having something so close to her usual weapon was an advantage, yes. York had the advantage of height and strength, though, and while Xion was used to dealing with opponents much taller, stronger, and heavier than her, those had been Heartless. Their fighting styles were simple, and easy to learn to counter. If York could keep surprising her and use his advantages well, he could win.

As far as speed went, Xion was quick. Quick enough to dart away after the hit landed so he couldn't follow up on it with another. The disadvantage of this, though, was that he was closer to the orbs he'd knocked off her vest. He'd probably get to them before she did.