What I did notice is a problem with skills, that are outside the GCD.

Example from my SCH.

Casting animation of my regular spells ends some time after the GCD is over and all buttons are not dark anymore. I'm able to cast a new Physik just right after the GCD is over. But I cannot use etherflow or any skill that uses the etherflows till the casting animation of my spell is done. So I've to wait more time, to use my skills, that are outside the GCD, than for the regular skills.

Hope I could write it understandable.