The Ohka would also require a new Betty bomber model to act as the mothership.
Its not as though the game really needs another way of killing ships anyway, we already have level bombers, torpedo bombers, jabos, shore batteries, ship's guns and PT boats. Besides any heavy bomber would do a better job of killing ships, you might even be able to do more damage/time with three or four jabo runs than one slow vulnerable Betty/Ohka formation. The only way the Ohka would have a role would be if the game were re-jigged to make level bombers as ineffective against ships at sea as they were in RL.