If Orochi is dead dead, his devil fruit better be used by someone else. Maybe someone that is actually already strong (Yamato perhaps?). Anyway, I don't see what use Orochi can continue to have in the story. If he comes back he'll have no allies and even though he has a mythical zoan, it seems he is not strong at all. He is a schemer but what possible scheme can he have now that he's alone?
Sigh, once again… In my theory, his zoan would become awakened and would take control. Or part of it. Doesn't matter how good of a fighter Orochi is if he's a super powered 8-headed and 8-tailed dragon.
If we're ever going to see an awakened mythical zoan, now's the right time. With such a weak user than can't possibly be a threat otherwise. And if he isn't supposed to be any threat, why even give him such a devil fruit. Ending things like they seemingly were would be something i'd expect to see in Bleach, with Kubo's erratic writing, but not here.