It doesnt apply to all classes properly. If your class has an “on next attack” like heroic strike, spell queueing does not work.
This is a very important lag reduction feature implemented into WoW that makes it so that your 1.5 sec lightning bolts are actually 1.5 seconds. Without spell que, a 200 ms ping would make your lightning bolts 1.7 seconds because you couldnt send the data to the server until the prior cast ended.
A warrior currently has his or her latency added to every attack that follows a GCD or cooldown. This can cost significant DPS and push off entire spells from the rotation over even a short fight.
This is a huge bug that some classes can’t properly use the Spell Que feature added to world of warcraft. How it doesnt have more attention is crazy.
To recreate the bug, go to a target dummy and initiate a GCD or cooldown. We can use bloodthirst as an example. When the 4 second cooldown is 90% completed, hit the hotkey a single time and watch bloodthirst cast exactly 4 seconds after it is ready a moment later. Do this exact same thing with heroic strike queued and you’ll notice bloodthirst does not cast. It cannot cast until the 4 second cooldown is entirely done and if you have 200 ping, bloodthirst has a 4.2 second or worse cooldown for you. It’s actually worse because it will force you to mash the key as it comes off cooldown and there can easily be another .2 sec added between key presses. I.e. how many times can you press a key in 1 second and divide that by 1000.
If you have 200 ms and a mechanical keyboard where you can mash the key 5 times in a second, bloodthirst essentially has a 4.4 sec cooldown… so -9% haste.