Judge class is technically already taken, it's the GMs' special 'class' that is exclusive to them (their unique gear is literally called 'Judge' gear). So that simply will never be added for players I'm afraid (also the whole law thing in FF Tactics Advance was a rubbish mechanic that just served to annoy players most of the time and was an unnecessary complication.).

And if you really want to be pendantic, the Garlean Legatee like Gaius were technically FFXIV's version of Judges story wise (based on the FFXII version), and, well, the Empire doesn't even exist now so that's another nail in that coffin.