This might not be relevant to aoe lag, but I think it fits the thread title "Sorry SE, but endgame won't work if you don't fix something."

As most of you already know, instant off gcd abilities are not going off instantly if you have just used any other ability, so I find it strange that actually boss mechanics require your interrupts to be instant, but combat mechanics not providing it as seen in the video:
http://www.youtube.com/watch?v=40a_c...ature=youtu.be