FFXIV Devs, why don't you just remove these from fishing if neither the players nor the Dev team is going to put them to use?
There are no fishing schools above grade 2, and seeing as fishing does not depend on locating multiple fishing locations. It's currently just another one of those mechanics that does nothing, and only confuses and likely frustrates new players.
I would suggest that if you do decide to put these to any real use, that you make gathering from schools reward better sp than simply gathering at any body of water.