+ Binding Heal overheal I sometimes take as a benefit of higher spirit too. You know youre taking heavy dmg (target of sniper+DOT on you) and you can precast/spam BH for a while longer to ensure you won'tbe down by some other glimpse of bad luck (add long run from boss jump/war song/whatever).
Atonement wont save you there and second healer may not manage.
Another tool available, another buffer for raid safety. Rather brute force tool, but still handy sometimes.
I write that only as a small explanation, your whole post was quite refreshing for me, I agree with it wholeheartedly.