I don't believe him to be legitimately mindless either, but I sort of interpret it as a malice-driven instinct that is so hardwired into his being that he operates on it; he is it. One of the compendium entries hints at Calamity Ganon's intelligence, so he definitely has a consciousness of some...
I don't want to see Ganondorf in BotW2. The corpse should be left as a corpse--which can be regarded as the source and heart of the Calamity--but I would have major issues if they tried to regress Calamity Ganon back to a human nature. If they attempt to personify him past the force of...