I don't really understand judgment by the publishers, because what if they all say that their players don't need to pay the PS Plus fee? Or what if they all decide to manage their own subscriptions? Seems kind of sloppy.

The best solution would be to have no FFXIV fee on PS4 but to require a PS Plus subscription. That way, you don't have to pay two (or more!) fees if you want to play more than one game online.