Due to the way I play World of Warcraft, I barely noticed the new ability queue system. I do not mash buttons, but press them when appropriate. In the new ability queue system, if you are on global cooldown or in the middle of an action, and press another hotkey, the game remembers that, and queues the ability, performing it after the first one is finished. If you play it right that is going to improve your ability output, because it gets around the problem of lag making you think you are still on cooldown, while in reality you are not.
But some people complain about the new ability queue, because they are apparently unable to hit a key just once. They are the button mashers, if they want some ability to go off, they hammer the key until it does. Only of course that with the new ability queue if you button mash, you will launch abilities twice which you only wanted once. WoW now actively punishes button mashing, and that is good. There is really no reason why a game should respond better if you hammer your keys instead of pressing them once.