Globally disliked changes, fix PVP with stuff that doesn't ruin PVE.
I had this chat with the earthen ring people who put forth this change. It was never thought through for lower gear levels at all. An I proved this by taking pre-bis shaman tank gear into BM an getting absolutely smoked on every 4 pack with a very geared healer. If you get hit by any CC and miss your first auto you are paper.
If LS and SS also provided the shield it MIGHT be okay. I just think it was an over engineered solution to a problem people made up. Paladin healers in PVP are far more durable then shamans and can also get 10% DR.
The reason they dont is because unlike the resto shaman talent tree, holy doesn't just suck.