The problem with "Instant OFF GCD" abilities makes combat feel less rewarding.

[Waliel]

Soooo.... really off GCD skills are on GCD skills. I have to hit it like 5 times to get it to go off, that usually takes most of the GCD.

What is the point of an off GCD skill then?

You only have to hit it once at the right time -- the time being half point of your GCD -- and the animations line up perfectly, so no GCD time lost, unless you use more than one at a time. Until the game decides to interrupt your skills and spells for no reason whatsoever, that is. Reactionary stuns, etc. are impossible to get off in time if you just used a skill is something I can agree on. There is also the problem of having to wait for the "longish" stun animations to finish for the effect to actually go through.

Translation, this is caused by the same problem as the AoE and server latency, we don't know how to fix it so you will have to live with it.

It's caused by not allowing you to overwrite animations with another, and we know exactly why the AoE latency is happening and how to fix it. It's because the server checks your position every 0.3 seconds and needs to be lowered to 0.1.