>>23084417I don't think so, but I won't rule out the possibility.
Diancie and Hoopa were kinda shitty until they got their powered up forms. Volcanion is really good already. Also Diancie and Hoopa's designs looked so simple and seemed they'd be expanded on with a new form. And while I know many don't like Volcanion's design, he doesn't look "incomplete" in ways that Diancie and Hoopa did.
But if anything, I'd bet a mega. It's the main Gen VI gimmick, and Primals only seem to apply to the lore of the ancient battle of Groudon and Kyogre.