I don't think (someone might correct me on this) there's ever been a Necromancer type playable class in the FF series. As this game is all about the fan service I wouldn't expect to see one coming in this game. Expect RDM, BLU, SAM, DNC etc, jobs with a fairly significant pedigree within the series.

Edit: I have corrected myself. Necromancer was apparently playable in FFV.