Merlwyb's dual-pistols felt like exactly the same sort of advanced tease of a job as Alisaie's use of a rapier in 3.4. I'd bet on a Gambler/Corsair equivalent easily. Outside of that I'm also hoping for some sort of Mystic/Rune Knight, though like Gosetsu in 3.5 we'll probably need to wait until the next patch to see any hint of that.

Otherwise they might do the GNB/DNC thing of releasing jobs with almost no foreshadowing.