Honestly I'd rather they DON'T change the way jobs currently work.
I don't want XIV to be the kind of game where you're just meant to skip to the end to start enjoying it and changing the way basic and early-game abilities work to fit a job's playstyle at max level while disregarding how it might affect the leveling process already made classes like Warrior and Machinist almost unbearably unfun below 70, I'd rather they do what Heavensward did where they simply add to the kits of each job instead of trying to rework them with every expansion.
At the very least if you're going to make drastic changes to certain abilities do it through traits that you unlock after level 71.