Are there any characters in Buffy or Angel that you wouldn't have wanted to see on each others shows?
Xander is great but I can't see what he would have brought to the table if he appeared in an episode of Angel. Also, he hates Angel so I can't imagine why he would go to LA anyway.
What? I don't understand you. Xander guest starring on Angel would have been epic. The fact that he doesn't like Angel makes the crossover so intriguing, seeing him forced to stay in the Hyperion Hotel and outside of his comfort zone would be great television. For the first time Xander will in Angel's group of friends. And it would force him to directly deal with his issues towards Angel, hell, they could go on a little quest and maybe get some respect for one another
And they could write some crazy reason for him to go to LA. What if the Hyperion Hotel needed repairs? Willow could send Xander to LA. LOL that would be hilarious.
Anyways, back to the original question, probably Dawn and Kennedy, because they sucked enough on BtVS
I don't know. I like Xander a lot, but I just don't see a place for him on Angel, especially if it was centered around him. I always, always wanted more crossovers between the two shows, I think my dream scenario would have been for one complete cast to go to the other show for an episode or two, but in terms of individual characters, some of the ones who are SO linked to one series or the other wouldn't really work on the other show.
I mean, could you see Gunn on Buffy, in an arc just about him? Or Lindsey? I couldn't. Just like I would have a tough time getting into Xander, Anya or Kennedy on Angel.