What purpose is that, exactly? Any healer with a brain is going to know when to be in or out of it, it doesn't require a particularly noteworthy amount of skill or forethought. It's occasionally unresponsive, which means even when you are using it perfectly you can still get screwed over by the game's own limitations. And, probably the most annoying of all, is that healers in PvP are reduced to nothing but healbots because they literally can not do any noticeable amount of damage.
Get rid of cleric stance, balance healer damage to be a bit lower than what it currently is in cleric stance, and make the role more flexible in what it's capable of performing.