Since Gold and Silver I have longed for cameos from past characters. Due to the 100% lack of them in RS I was just desperate for some references to old games.
Obviously that's changed in recent generations, especially regarding B2W2.
I'd love to see a few appearances from older characters, but only if they make sense, really. Jasmine appearing in DPPt was nice, and of course it was a little hint towards a GS remake, but..
Why Jasmine? I mean it didn't make me think 'They are DEFINITELY' making remakes, it made me think 'Am I going to be able to battle her? What else will she be doing?' The answers being 'Nope' and 'Nothing'.
The PWT is awesome, but not really a good basis for cameos since they're literally there to be battled, nothing more.
As some people have mentioned, I kinda hope Cynthia DOESN'T make a cameo. She's awesome and amazing and cool, sure, but I've had enough of her now, and want to see a few RS characters, maybe even go back to Kanto characters (which are pretty much covered from HGSS, sure, but.. yeah).
Seeing Steven again might be cool, or maybe even Wally or someone. He was a character with a set team and role, so it's not like they'd have much ambiguity to cover.
I guess I'll have to wait and see!