If the devs keep consistent with their internal rule to keep the game simple (as happened with the removal of the elemental table), gear will be shared.

With glamouring, telling your class by your gear has been gone and done (thus, we now see the class in clear in pvp) so I don't see any reason to have a new separate gear set. It will be more nice, instead, the new job comes with its new theme-related gear, but wearable and glamourable by any job with same main stat.

Going maybe too much far, I will love see one day the separate sets of gear being only five: str/vit/int/dex and mnd based, with the job having access to one or two of them for use.

And all of them for glamouring of course.