Dunno if it's ridiculous or not, but I did think of a possible way to implement blue mage. From my understanding it seems the biggest issue with the job is how learning spells and abilities wouldn't work well with the way the current system is, and also where would it fit in as a role due to the fact a true hybrid job wouldn't really work well. So here's my idea:

As for where the job would fit in it would be able to be all 3 roles in a manner of speaking. How this would be accomplished would a be a sort of role lock system, perhaps the soul crystal for blue mage is divided into 3 pieces, each piece representing a specific role: tank blu, dps blu, and healer blu.

How spells would work is there would be 3 classes of spells and each class of spells would only be usable by it's specific role: tank spells, dps spells, and healer spells. This would essentially lock spells out of being able to be used with roles outside their own role category, and prevent over inflation of actions necessary to the job overall, while still giving the job multitudes of diversity and adaptability (at least as far as being able to change roles outside of combat and instances)

As for how spells would be learned (from my understanding this is one of the bigger issues due to how abilities and spells are already handled) you would learn spells much in a similar way to how they are handled in other final fantasy titles, watch the move/spell activate with a chance to learn (albeit not nearly as bad as FFXI). Many people think this wouldn't be feasible due to how we already learn spells, however I would suggest that blu should take a different approach to this as well.

For class quests and leveling gains in general I would have blu learn spell boosting abilities and additional passive traits instead of acquiring new spells. This could give the job an even more unique method of playstyle as each ability could work differently based on the current role that the blu is locked into.

Now some of the issues with a system like this for blu are pretty obvious, like would you have to level each role or would it all be tied together, or how the job would play before learning spells, or even what weapon type they would use. Questions like those would likely have to be decided by SE and what direction they would want to take, however I think this method could possibly work well and could even devise a whole new expansion in which to include the job to fit in with the lore of said expansion (similar to how blu was in Treasures of Aht Urgan for FFXI).

Thoughts?