Almost all of these conps and their variants are top teir and incredibly frustrating to play against since they involve constant CC, pressure, and survivability.
I hope every warlock/shaman team gets aids in real life.
KFC and MW beastcleave (the comp you run the most) are all extremely strong comps vs warlock teams.
Also people don't completely complain about hunters because they're the best class in the game, they complain about hunters because the biggest morons succeed with them. People don't always complain about what's best, they complain about what's faceroll and easy (hunters). In reality the difference between a top tier warlock like Dota, Chanimals, Snutz etc., is insanely different between random morons.
Also, it's not warlocks that are the main reason for those comps never dying. It's shamans. Or even moreso, lock shaman synergy.
TL;DR people complain about hunters because idiots do well (myself included) with them, at least the locks that do well have brains.