The lag is by design so of course they're not going to say 'oops maybe designing our MMORPG to be unlike any other MMORPG was a bad idea'. About the best you can hope for is adding another 0.5s to most abilities that are too difficult to avoid without memorization. Remember, the 0.3s happens twice. First when the ability is displayed on your screen you're seeing the rendition late (if you've a running start on WotL it is very obvious this is the case), and a second time when you're trying to get out of the AE before the castbar finishes, so 0.5s is about right without memorization.