Most enemies out in the world just have generic 'get out of the orange aoe' attacks.

More interesting attacks are generally reserved for boss fights, or on occasion dungeon mobs the one in Arboretum hard that will transform you. But in general, enemies out in the world in FF XIV lack unique and interesting abilities.

Whether I would like a traditional blue mage or not is irrelevant here, my point isn't that I would dislike it, but that it goes against the design of this game. It wouldn't fit. Every other job goes through changes to fit into FFXIV's strict trinity system mold. If blue mage is added I have no reason to believe they would be a special case, the one job not to bit fit into a tank, healer or dps mold. THey changed Dark Knight. They changed Summoner. They changed black mage, they changed red mage, they will change blue mage if it's added.