I agree, there is no problem with fanservice as long as it is not over used.
If we think about it Crisis Core is a huge fanservice. Does it work ? Yes! Does it break any aspect of the game, no. It's not as if square is saying Aya will be using bikinis, it's just some tear on her clothes, much less then Goku in Dragon Ball.
Back to the game, I just it delivers. Whatever it tries to be, be it survivor horror, 3rd person action or RPG, I just want a good story and gameplay.