Beastmaster, because it would have vastly different mechanics than any other job in the game if they stay true to its' origins. I touched on this before, but I feel like other jobs are simply rehashes of what we already have. "Tank with a Gunblade instead of an Axe," the end-goal and overall premise is the same. BST would be something totally different.

In my opinion, with all the potential jobs out there, BST would bring the most players. Nearly every mmo has a beast pet class, many are awaiting for XIV to implement one.