Well, judging from that article that explained what happened, Kozaki coming back was kind of because they were in a bit of a rush to get things going after getting the green light to make another FE game, and they weren't sure if they could find someone to fulfill the character quota for the game.
So since Kozaki had prior experience and the dev team liked him, they voted to bring him back and he accepted.
So, I think they might get someone else since I think they probably already have an idea of what to do next since Fates it sure to sell enough to justify more games.