Region could still have a different localized name, it's been awhile since it happened but Unova was named Isshu in Japan.

Regional forms could be confused with the ancient/future forms/subspecies like Jigglypuff and Amoongus (which we now know will have different names) so even though we saw a Meowth in the trailer it could still have an alternate.

Gimmick could have been misconstrued as the past/future forms (when that is more-so like regional forms than a gimmick), could still be called "tenses" instead of regional fakes.

Charizard forms could come in DLC ie; GMax forms in SwSh DLC.