"So what is a limited job? Yoshida explained that it’s based on one of the fundamental notions of Blue Mage, that it’s a job without balance. Part of the fun of the job is using powerful techniques that wreck game balance. The developers didn’t want people walking into a high-end raid and using Level 5 Death to kill the bosses instantly; at the same time, you don’t want to get a Blue Mage queued up with you who hasn’t learned necessary abilities at a given level. Hence Yoshida historically saying that the job is difficult to adapt.
How do you do that while maintaining party balance? A solution was finally found: you don’t. You let the job be limited, designed for solo play rather than parties. Blue Mage cannot queue up for duty roulettes, any duty requiring matchmaking, PvP matches, Deep Dungeon content, or even certain other content that may not yet be revealed. You can enter instances with pre-formed parties, however.
If this sounds, well, limited… that’s by design. But Yoshida stressed that the point here is that there’s fun stuff to do with Blue Mage and you get to have fun with the job, first and foremost. Rather than making it not feel like Blue Mage, it feels like it should, and it opens the door for other fun limited jobs that may not fit into the game’s role-based party structure. He brought up Beastmaster and Puppetmaster as specific examples, to a chorus of cheers before noting that he was speaking hypothetically at this time."