I would like to see Fisherman class be useful in Endgame. Maybe have a Boss that can only be fished using a "legendary" rod. Or have it where a fisherman can buy a boat at high level and ferry party members to an Island (like an instance) to fight special Notorious Monsters.

Another thing I would like to see is Legendary Bosses inside towns. Maybe have a Giant Squid that resides under Limsa and you see giant tentacles coming out of the water or a giant Mountain NM that roams around Ul'dah and can stomp you if you get too close. Have a dungeon inside of him.