I was looking at what 51 Purifer gives over just 16, and I'm going to try a heavier Sentinel build with just Ward of the Ancestors.
I'm curious, why do you suggest 28 Purifier, Mann? What is it you feel is worth getting from those 12 extra points? It has no impact on your SotA or WotA shields, you don't get GotA, and you don't get RotA. And you definitely aren't getting Spiritual Conflagration.
All you seem to get is Searing Transfusion (it's pretty weak for a 1m CD) and Flashover (this might be worth it, but only requires 20 points, not 28). So I could see going to 20 Purifier. Why the extra 8 points? Blessing of the Flame and Latent Blaze?
This is what I'm giving a shot: http://rift.zam.com/en/stc.html?t=00...szco.Ex000z.-6
Tidal Surge is superior to Flashover (I think; maybe I'm wrong), and also getting +10% max mana, Crushing Wave, Healing Flood, and Restorative Tide. Losing out on Searing Transfusion, Flashover, Blessing of the Flame, and Latent Blaze.
I'm torn on the Healing Invocation boost or the +Crit heal boost. Seems like the +Crit is going to perform better regarding straight Healing Done #s, although the Healing Invocation boost might be more useful to keep a single target up.