I don't understand BLU defenders

[kikix12]

The live letter straight up said that it was going to be in the caster DPS role. I'm confused about why people think they will be able to set up their skills and be tanks or healers.

There are people that do, but there are many people that know that Blue Mage won't be able to become "green" or "blue". But in pre-made parties or unsynced runs, the only ones in which Blue Mage can take part, role have zero effect. Just yesterday I did run a dungeon (I believe it was a roulette, even) with healer, DPS and two tanks. So a party of four Blue Mages is very much possible.

BLU will be using caster role actions and caster gear. It won't have the defense or MND to do the other tasks. They have already said this in the live letter.

You see, THIS is the problem and this is why Blue Mage have the potential to be absurdly broken. This class historically have skills that have unique effects...and powerful at that.

For example in Tactics Advance, Blue Mage had Dragon Force which SIGNIFICANTLY increased ALL stats for the entire battle. Like, so significantly that a Blue Mage that used it was as tanky as the tanks. And since it upped STATS, you could stack it with protect and shell for further reduction.
There was also White Wind which heals damage equal to the amount of HP you have...in an AoE. Angel Whisper which heals and bestows re-raise. It was so broken that in sequel to Tactics Advance it couldn't target the user anymore. In FFVII it FULLY heals a target, removes some status ailments and works even on DEAD players, basically being a full-revive. Drain Touch which deals good damage and restores HP equal to the damage dealt. Not like Drain which is a weak skill hence offers weak healing. And those are only some skills that have the potential to be broken healer/tank skills.

So yes. A Blue Mage, depending on how crazy they will go on the skills, can be the BEST tank and the BEST healer in the whole game, despite being locked to a DPS role and DPS casters stats. Because its skills don't even CARE about its stats outside of damage.