I hear what you're saying buuuuuut people just kinda assumed the crystal shard things would line up with it cause they assumed it makes sense. We don't know if synchros are gonna be connected to the stones or amie or something else entirety or if they're even gonna be in the game.
What we DO know is that the anime (which is made to promote the series) is making this a BIIIIIG deal and a huge story arc for something that's not in the games at all nor is needed in the anime as filler. I mean, hell ... I figured there wasn't gonna be a Z version even with Serebii yapping on and on about how the 6th gen aint done yet and how there's gonna be a Pokemon Z cause of the anime. IMO the Z stuff in the anime was just that, anime filler. Turns out that that feature is in the game to even though it's a new gen

(I'm referring to zygarde and it's transformation bs)
I don't really think the anime makes big deals like this about stuff that's not gonna be in the games in some way. Not any more at least. I mean, they could just as easily get a mega evol arc with Ash instead. But this ... this seems like a something beyond that with out any reason to be in the anime if not to promote a new feature in the game.
Also, it would be super simple to make synchro evols that match trainer features. There would be a base mesh for the evol and there would be some lil part or parts that change with hair style. Everything else would just be texture changes to match parts up and make it look like that pokemon is channeling THAT trainer.