Quote Originally Posted by ChazNatlo View Post
If we assume that there will come a time that we only see one job in an expansion, it could make sense for it to be with 7.0, since that fills in the only stand alone armour set. However, in theory they could add new armour sets and possibly shuffle them around. At one point Scouting was a new armour set (Though part of me feels like I remember Ninja sharing a gear set once upon a time, like at the end of end of 2.X when it was introduced. I can't recall if this is accurate or if scouting has always existed for NIN.)

Hypothetically if they were adding Mystic Knight as a Melee mage, they could split Red Mage off from the casters and have them share an armour set (though I admit this is "they could" not they would or they should. I wouldn't even give betting odds on this theory it's such a long shot.)
When NIN was added what they did at that time was add dex to the ARR striking gear and let NIN use it. So back then they shared gear with MNK