It would be great if it weren't on the global cooldown, but still trigger it. Sucks doing a basic attack chain and boss happens to do an eruption and you're stuck on the gcd. Having it off the gcd means paladins who spam it won't be able to get use out of it and shows better skill on those who can control it vs not, and lets players see who can perform better than others. Right now we have to throttle threat/actions vs stun and it's quite boring and/or frustrating.