To be honest, I'm not bothered by their proposal on the job... But I really think it - could - have worked out as a regular job if they wanted. Making BLU fill a ranged caster on the support niche together with BRD and MCH.

If they themed one Blue Magick per class ability, they could easily fill 25 abilities. The flavor of the support would be defined by what blue magicks you'd assign to the active slots, so BLU could represent a really creative kind of support.

The whole lv5 Death debacle is really pointless as in most of the series, bosses are actually already immune to it.