I love fishing. I love it alot. But it definitely needs more utility, at least for the high-end fishing. As far as end-game fishing goes, the only big game level 50 fish that has any utility at all is the Mahi-Mahi, and you're better off farming easy-peasy Red Coral if money is what you're after.

There's nothing more fun than catching a ginormous HQ level 50 two-star fish with some epic prehistoric name and appearance....and there is nothing more disheartening than selling it for a couple gil because nobody cares that you have a Giant Donko.