I agree with most of what you have here...but considering you are only using 1 melee attack every 14 seconds (unless silenced), Aggressive renewal should still be the better choice for regaining mana over endless winter.I haven't had a chance to parse this is raid situations but after some dummy parses I'm looking forward to trying
If someone already posted something similar I apologize in advance.
In the build I omitted clinging spirits because my guild's inquisitor/inquisicar keeps it up consistently so I don't need to. I may change that if I were raiding without another inquisitor/inquisicar. I omitted agressive renewal, it is a DPS loss and regens less mana than 1 pt into Endless Winter. I only put 3 pts into castigation assuming the archon will have a cast time reduction buff up only 3 pts are needed. I put 2 pts into symbol of corruption because even at 5 it wasn't a significant DPS gain but I expect a higher boost from it than having redundant clinging spirits in the build. I used Circle of Oblivion to give just extra functionality on fights like Matron where some AE damage may be desired (if your guild uses tomes you could pop soul drain and CoO to help AE down the adds) Shaman points seem to be pretty standard. I did add a single point in endless winter and noticed that after an 11 minute dummy parse I was still at 100 percent mana where previously I could only get 4-5 minutes tops without going OOM.
I still have DoT's macro'd for simplicity's sake and don't really feel that changing it was a significant DPS increase. The potential for DPS decrease seemed greater if one of more DoTs were not refreshed when they fell off.
Using this build I completely allowed all DoT's to fall off including Sanction Heretic before reapplying. Reapplying SH on proc from the inquisitor crystal was a significant DPS loss.
I welcome feedback on this and will be testing it tonight on a couple of fights and posting parses after.