Resto shamans have received a pretty nice change on the PTR, with Purification increasing the output healing rain by 100%.
This is a great change, and I can see that this change, combined with the newly redesigned Conductivity talent, will likely make conductivity be the go to talent for resto shamans in any site where the raid is primarily stacked up, or even for primarily melee heavy raids where you can easily drop healing rain on the tanks and melee and have it be there for the entire fight.
Healing rain was quite powerful for nonhealing Shaman specs, so it is nice that there is such an increase for the resto version of the spell, rather than it being nurfed.
They have also added the change that the Glyph of Healing Storm for Enhancement Shamans no longer increases healing rain.