Some people bring up RDM as a job that was ‘shoe-horned into the role system’ and ‘why can’t they do the same with BLU?’
Well, despite personally not wanting BLU to be a typical caster anyway, I don’t think RDM was all that bad a fit.
Red Mages are known for using white and black magic, and physical attacks, and FFXIV’s RDM ticks all of those boxes. XIV’s lore actually made it a very good fit with elemental spells being split between white and black magic, and it still has support skills to make it somewhat of a functional white magic user.
Blue Mage on the other hand, isn’t typically known as a damage dealing job as much as being a gimmick job. You have a focus on collecting enemy skills that do all of these gimmicky effects. It’s not known for its Shockwave Pulsars and Shadow Flares as much as it’s known for Bad breath, White wind and an array of level based spells, plus heavy use of elemental exploitation. None of that could be squeezed into the role system.
To sum up, I don’t think Red Mage lost that much to the role system, but I think Blue Mage would lose too much.