>>23242829the designs are a bit lankier, in bw things are oversized in a cartoony manner (compare his cheekmarks, although its just a single frame you should see the obvious difference) and a change in attitude helps a lot too.
XY Ash is a really strange case because he feels like a matured version of BW Ash (Episode N) yet he has traits that can only come from experience (DP/AG). His battling ability seems to come from DP yet BW had almost none of it yet he learned.