I think the best thing to do with those "Specific" style jobs like Blu and Bard is to blend them with similar tasks to make the Weapon class then have the Job for each specialization.
Bard, Gambler, Corsair, Beast Master, Puppetmaster could all stem from the same Weapon Class "Entertainer" while Each of those Jobs is its own job.
Same with how I described how they could implement Ninja, Samurai, Mystic Knight with Oriental Weapons being used by the "Vagrant" weapon class. http://forum.square-enix.com/ffxiv/t...ing-SAM-NIN%29
For things like Blue Mage, You can mix Blue Mage, Geomancer, and some of the Beastmaster skills together into a Weapon Class then let players build the core Blue Mage, Geomancer, Beastmaster jobs out of it and pull whats missing from that weapon class for those jobs from other weapon classes. .