Thanks for the replies!
babylon - You detective! :O Thanks for taking the time to look... I hadn't thought about Ancestral Healing, and as you saw, in the guild I am 95% of the time paired with the Restro Druid and Resto Shaman (we're the healing team!). I would imagine that, even with Ancestral Healing, Inspiration would still provide an additional 10% physical damage reduction... for a nice 20% on our tank. I guess then it just comes down to sacrificing that 10% physical damage reduction for some all around better healing, including tank healing, which I think may indeed be worthwhile. :>