Hmm I just don't see Ninja as a Pet Job, I would think such label should remain in the hands of Beastmaster, Puppetmaster and Summoners. Heck even Dragoon too~ I miss that wyvern they use to have.

I guess I'm a bit reminiscent of XI that I didn't even notice I described a XI ninja earlier xD, but I do think Ninjutsu attacks (Through the basic elements like fire, wind, water, etc.) + DD from behind + abilities to bypass aggro, would be a good mix of skills for a ninja for FF14. All they would have to do is not implement the shadow clone skill then voila~ It no longer can be a tank. So they would be about utilizing ninjutsu + DD skills from behind, perhaps making combos out of it to increase their damage potential.