I'm not sure Laguna is the sort of person Xemnas would actively dislike, he doesn't come off as dangerous enough to be worth disliking (sorry laguna!!). Tolerate unhappily perhaps. Laguna's enthusiasm is scary. It's like a grown-up Sora, with a machine gun.

...I think it's almost better he was in Dissidia. As much as I like seeing people in Kingdom Hearts almost always they're pretty de-aged and... the whole Leon thing would, yeah. Become REALLY WEIRD. But I'll be happy to throw Xemnas at him anyway. 8D