I think his Gerudo form would be obtainable after an event like being revived, especially if it's with human blood (Link or Zelda's) rather than through witchcraft.
With a lot of lore, the blood of a subject usually has a lot to do with the final outcome of its use. While revival is possible for Ganon, the specifics haven't really been given. I like to believe that human blood would create a human form, just as witchcraft/dark magic created monstrous forms (Shadow Link and dementedcrazypigGanon).
Plus, he managed to create a Gerudo body out of thin air in TP, but maybe that's because he was initially executed in his human form. If the form he is defeated in plays an important role is his reappearing form, then I'd say he's stuck as a boar.
But I like his Gerudo form and hope that the way he is revived is what matters... That way we can see 'Dorf again.