My problem with GCD is as a healer using my poison cure spell is not worth wasting my time via GCD. Why you ask? Every poison i have seen is aoe hitting most or all the party with 10sec timer, 2 sec per cure poison GCD means it takes 8 seconds to cure each person on effect at time you can have 3 or 4 stacks hit each player the same time that would take 32sec to remove where the poison ends in 10secs. So it is just better to spam heal due to GCD