Predictions for job(s) in the next expansion?

[Archwizard]

They'd probably just do what they've done with old Loot tables in the past when making some sort of change and just do nothing. The old scouting/striking/maiming gear would still exist and the jobs that can currently equip it would continue to be able to do so (and should they add a new job they'd be added on to existing gear as well), but whatever gear they implement going forward as "Slaying" which encompasses Striking/Maiming/Scouting would be the only option. That's what they did with accessories in ARR/HW, all jobs could equip any accessory class, but when they changed it to lock Tanks to Fending accessories and Strength Melee to Slaying accessories they didn't go back and alter that gear, the change was only made for the gear moving forward.

Then doesn't it seem moot to base the assumption of jobs moving forward on the gear sets, if it only affects a handful of sets moving forward anyway?

I mean the way I see it, it seems like the point wereotter is making about armor sets is about designing gear. Now, armor and weapon visual design is different from the balance and design of job mechanics; if the concern about not adding new jobs is about keeping their mechanics from being homogenized and imbalanced, then that doesn't affect armor visual design at all since they're worked on by completely different teams.
Mechanically, even in the example given, the stats themselves dictate whether the jobs actually want to use the shared accessories available to them, and those are generally programmed in based on a static threshold of values for each gear level. The armor itself hardly matters in the question of balance, so long as a job doesn't have a ridiculous attunement to one stat or other, and multiple sets will be available options at higher gear levels anyway.
Visually though, putting a heavy knight-like Dragoon in lighter, mobile Monk/Samurai gear will be jarring, as will putting a stealthy Ninja in flamboyant Bard/Machinist gear with wide-brimmed hats, and vice versa. Considering they elected to give Ninjas, Monks, Bards and Dragoons their own separate armor sets in the first place back in ARR, even when some of them shared primary stats, which do you think impacts their decisions about new armor releases more -- stats or aesthetics?