That's not all that is very delayed. Procs and debuffs. All combos are proc'd by other abilities, but it takes 2 full seconds before the dotted outline appears on an ability that is proc'd. It's even worse with a Pug, you don't know if your stance changes and the next ability is ready until the GCD is pretty much finished. Your DOTs don't show up on the enemy for 2 full seconds as well. So as an archer, putting on your procs(which don't always land), you don't know if you need to use it again, because it didn't work, until AFTER your GCD is done and you're already on your next ability hit.

This is my single greatest complaint. These delays take out any need or reward for good reaction time and cause some serious inefficiencies while using(or wasting) your abilities. Which is game breaking, considering you already have an unacceptably long GCD anyway. almost 3 times the normal length of any game.