One major reason why we(warlocks) are now in such bad state is because Xelnath - our class developer that made MoP version of the Warlock, was fired near the end of the MoP, and now, no one in Blizz doesn’t give a crap about US. Just look how our specs work right now, it is clear that person who was involved in Legion or BFA warlock rework, doesn’t really care about us.
Juts look at gameplay bugs that are still present.