I think we're at a point with jobs that it'd be a better idea to introduce new classes as specializations for existing classes rather than complete jobs. Something like a Time Mage or a Beast Master would either have too much overlap with an existing job or not enough to create a whole class; but if Time Mage was a healer specialization that offered a couple new abilities and some traits and Beast Master was a BRD specialization that did the same thing, then you'd have a cool way to augment existing classes and freshen them up.