IMO, RDM is a great job that is simplistic to pick up, with a good amount of nuance beneath the hood. Within FFXIV's world, where BLM is the elements of fire, thunder; and ice and WHM is the elements of water, earth, and air; RDM can use fire, thunder, earth, and air. Amidst all this, the casting of magic charges their sword to deal magical thrusts. It meets my fantasy of a spellblade, and is a jack of Black Magic, White Magic, and melee combat, but a master of none; it uses a combination of its three arts to grant it power on par with masters of any of the aforementioned elements.
That's the imagination I was hoping for with BLU; I don't care about Final Fantasy so much as I care about FFXIV. If I wanted FFV's BLU, I'd boot up FFV, as it were. If I wanted FFXI's BLU, I'd boot up FFXI.