It was actually one developer who championed warlocks in MoP, and there's a pretty interesting backstory behind what happened with them, how the class was revitalized, and then the dev was eventually fired when he grew bitter and aired Blizzard's dirty laundry in public. He wrote about the MoP warlock dev process on his blog. Great read, strongly recommend.
http://xelnath.com/2018/05/15/the-mo...ew-you-missed/