SE, the concept of "Limited Jobs" is a really bad idea, turn back now

[Anesteria]

We've been over this Physic.

They could have done whatever they wanted with BLU and it would have worked precisely because it's a job that could have worked either way. If they made Red Mage fit, they could have done the same for our beloved Blue Mage, full stop.
Identity is a really poor excuse when what defines BLU is only the fact that they get the skills from monsters and use it under variations of magix considered "Blue".
Could have only allowed DPS abilities with the one "iconic" spell on a big CD White Wind, Red Mages are DPS and get Raise and Cure + Dualcast.
Could have been a mage tank if they wanted.

That's how versatile BLU is. And it would have been fine to pick one of the routes and stick with it.

For the "limited jobs" i'll just go with the Miyazaki meme:

"Limited jobs were a mistake"