>>41852561the rotom dex is annoying in practice, but at least it makes sense conceptually. there's no real reason why charizard needed two megas other than that it's CHARIZARD from KANTOOOOOO.
they also didn't make the rotom dex to pander to sinnoh. they made it to pander to japanese kids who liked yo-kai watch. it was a transparent attempt to copy whisper's role in that series.
even then, they still couldn't help themselves and ended up making a porygon dex for pokemon masters. they just couldn't let another region have something that their precious KANTOOOOO didn't.