I understand this. I asked in free company why I would want to use Bloodletter over Heavy Shot. Became a big thing with a raider in the FC deciding to be a jerk and getting blacklisted. I asked why. All said instant and not on GCD. The problem is that this instant spell animation is as long as GCD. At least when I use. So I ignored them and moved the ability away from use. I don't understand this as some abilities it seems like I can interrupt and there are others that I can not. I would enjoy at least having an ability that broke current animation to allow a different ability to be used even if it had a 30 second cooldown. Could at least make a macro then for what ability you normally would need instantly.