Realistically, Blue Mage is a means to refresh interest in content that is one tier old, just now with an overpowered role with superior healing, mitigation, and damage. It does... exactly that.

Absolutely nothing wrong with it. It doesn't need to be a main job, and it doesn't need to be "balanced". The imbalance is what makes it fun, as you're pretty much doing DPS a good 80 iLevels above what other mages would do at the cost of having much worse armor and complete RNG on mechanics. It changes the way you engage with old fights, and I love it.