They announced they're adding another limited job next expansion, so I would be more inclined to believe blue mage isn't getting reworked into a standard job.

But not just that, if they did change blue mage into a standard job, it would remove the entire blue mage spellbook and create a situation where all spells are learned at set times and intervals and every blue mage would have an identical toolkit 100% of the time in order to keep the job able to be balanced with other caster DPS, would eliminate all healer and tank skills, and render all the blue mage achievements unobtainable.