I can understand some peoples concerns about them keeping up with the growing selection of classes and keeping them balanced, but really adding one unique class is not going to blow up the rest of the teams ability to manage the game, add content, or balance existing classes. They also have such a massive backlog of unique abilities and skills that they can configure or reconfigure that they don't necessarily have to just remake an old class, either.

My own thoughts are they should probably look at final fantasy tactics and try to draw from there, since that game drew from games like Tactics Ogre and forced out of the box thinking. The kind of skills that are historic final fantasy they haven't tapped into yet are Holy Sword skills, Mantra, Geomancy, Dark Arts, Yin Yang Magic, etc. They also haven't tapped into Sword Saint, Templar, or Rune Knight skills yet. Albeit, I think this is why they are trying to come up with an original Job: Classes are linked to weapon groups, so having another class that wields a sword would mean having to come up with a new base sword weapon that is different from paladin and dark knight. Hammers are not used yet, but coming up with a class that wields hammers kind of limits existing skills. Not to mention hammers are not very glamorous weapons, either. Maces are another option along with fans, scythes, Chakram, chain / whip (hello vampire slayer?), crazy floating magic stones / materia, etc.