Literally every single one of everyone's worst fears for the ending of XYZ has been confirmed by just two episodes. Serena leaving? Check. Ash dumping Greninja? Check. Never rematching Alan? Check.
Also a lot of people were hoping that Alolan "what's a dragon type?" Ash would be a reboot rather than a continuation. But I don't think all of the above would be happening if it were a reboot.
worst fears? you dont need to fear something that you know will happen. it is an unchanging tradition. partial or complete secondary character overhaul, and ash entering new region with only pikachu. This and the shallowness of the show has made me stop watching since johto