What you want is /stopcasting. I am not sure what problem you are having with it but if you want to stop what ever you are doing and heal than that is /stopcasting. The biggest hurdle should be getting out of the habit of spamming the button. spamming button and /stopcasting are not your friend.


Why do you have all your shamans healing? I use just one who usually alternates between LB and Heal. If things get hairy I will pop insta cast or hit the modifier to heal-all.