Unfortunately Judge is already taken - it's what the GMs are (their gear is literally called 'Judge' gear - Yoshi's alter ego The Wandering Minstrel also wears the latter attire). This is further reinforced by how in the Garlean Empire the supreme commanders are called 'Legatus' not Judge (despite otherwise being FFXII's Judges in all but name).

Just like Onion gear practically precluding any Onion Knight job in the game, due to the GMs already taking Judge as theirs I don't see Judge appearing as a player Job alas.