If the hash moves back to BTC, wouldn't unknown just pick up the slack back to ~90% again? We already know "he" loves it so I think it chugs on.
Or...He just takes a 12hr breather and the difficulty drops like a rock.
The difficulty will be much higher than before but yes its possible that it will be manipulated again to cause a drop but you may find other may jump in and take up the slack to stop it especially now there are more pools setup to mine this
Whats most likely going to happen is there will be miners jumping back and forth which will cause the BTC difficulty to drop steadily until it all eventually equalises