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

[Calypsx]

I usually just press my instant off GCD abilities when the GCD timer hits the half way point after a skill. It always works and comes out when I press it then.

I actually kind of like it, it's improved my timing and play so I don't mash keys anymore and all my moves are smoothly transitioning into each other with added buffs in between each attack. I'm also learning to read patterns and study enemies instead of twitch reacting to them.

Different strokes for different folks I guess.