At this point I'd be more surprised if they didn't add BST, absolutely.

However I'm more intrigued by an NPC that is using Urianger's old mechanical staff. The weapon type of unreleased 1.0 Arcanists that had a schtick of summoning "distaff" that theoretically would have functioned like 3.0 MCH pets - placed "totems" that would deal damage or buff/debuff in an area.