One big factor as to why we dident see MM in AWC is due to rogues. If you remove the rogues you could slap a random rival MM hunter in there n he´d kill the mages while backpaddling.
Mage prevents warrior from being picked, rogue prevents hunter from getting picked as they simply cover eachothers weaknesses as they have for 20 years.
As such AWC is far more about teamcomps than it is about individual class n spec power. If they removed rogue from AWC we´d instantly see a ton of other classes appear n mage would appear alot less by default as locks are kinda mehh atm leaving mage with no great teammate except for feral.