I rather missed the Team Rocket rivalry between Jessie & James, and Butch & Cassidy. They were totally absent from the Black & White series. Always fighting over who could say the motto better had me chuckling. Also, to me it seems as if Jessie & James have gained the competence that Butch & Cassidy had in previous seasons where they appeared, a bit serious at times, but still goofy. Maybe the writers gave Jessie & James their attitudes to wean off Butch & Cassidy?? I also miss the other running gags with them, such as nobody being able to get Butch's name right, and when the two could never pronounce correctly the name of the Professor / Dr from Team Rocket (I forgot his name ^__^). So would anyone like for the Butch & Cassidy to return in XY? I think it would really bring back the old personalities of Jessie & James, which is what I thought the writers were trying to do again.
I do wish that they would return for an episode or two. I liked Jessie's and James's rivalry with them. Not only that, but I laugh from everyone mangling Botch's name xD
Do I think they'll return? No. BW broke a lot of chains, especially with recurring characters. It seems that Jessie and James have grown well enough to the point of equaling themselves to Batch and Cassidy. If they were to return, however, I'd expect them to have grown more than Jessie and James, possibly causing some big conflict that could end up as an arc.
Since the TRio had gotten a promotion in Black and White, it would be fitting (and honestly quite fun) to see Butch and Cassidy make an appearance again, but with a higher rank than Jessie and James. With the lack of development and poor writing for Team Rocket last season, a return of old rivals would make things interesting for them once again. Not so sure it will happen though as much as I would like it to.