GHW can fill the role of heavy tank damage phases when mana restraints will kick in. In HPS terms we have HS>GHW>HW and in HPM terms HW>GHW>HS. GHW is the middle ground. And there is also no reason to heal the target of a random single target boss effect with HS, if it is not in intermediate danger of dying. Also, GHW can be precasted to end with the impact of casted special boss attacks. To use all the healing tools we have in the right circumstances and keeping an eye out for these opportunities will seperate the excellent Resto-Shaman from acceptable, in my eyes. But we will see after the first HM kills, if such skill will be rewarded.

Calculations I've done indicate that HS actually has better HPM than GHW when you have TW. This is because of the increased HS crit chance from TW granting more mana from IWS, and is the case despite the lower IWS proc chance from HS. Of course, HS also has better HPS than GHW with this crit chance increase, due to AA, and also increases AH uptime (albeit perhaps by a negligible amount in a raid). HS is also just plain faster, which means more time for Lightning Bolts, repositioning, etc. So unless I've erred in my calculations, it may be time to move GHW to an out-of-the-way keybind.

The base healing amounts I used in my calculations are estimations of the average - I wasn't able to find the actual values. Corrected values would be great but these should be close enough to tell us which spell is better.

Assume Tidal Waves, with 30% additional chance to crit Healing Surge.

SP = your spellpower

CR = your crit chance

HST = your haste

HS_basehealing = 7697
HS_coeff = 0.604
HS_casttime = 1.5 / (HST + 1) sec
HS_truehealing = (1-CR-.3)*(SP*.604+7697) + (CR+.3)*(SP*.604+7697)*1.8
^ non-crit heals ^ crit heals w/ AA
HS_basecost = 5946 mana
HS_truecost = (1-CR-.3)*5946 + (CR+.3)*[ (.6*4201) + (.4*5946) ]
^non-crits ^crits w/ Improved Water Shield's 60% proc
GHW_basehealing = 10255
GHW_coeff = .806
GHW_casttime = 2.5 / 1.3 / (HST + 1) = 1.923 / (HST + 1)
^ Tidal Waves' 30% cast time reduction for GHW
GHW_truehealing = (1-CR)*(SP*.806+10255) + CR*(SP*.806+10255)*1.8
^ non-crit heals ^ crit heals w/ AA
GHW_basecost = 6607
GHW_truecost = (1-CR)*6607 + CR*4862
^non-crits ^crits w/ Improved Water Shield's 100% proc

I've posted a very rudimentary spreadsheet with these formulas plus HPS formulas on Google Docs, linked below:

https://spreadsheets...MXc&hl=en#gid=0The inputs given are my current self-buffed stats. (My Shaman is just barely in heroics...)

Playing around with the inputs reveals that HS will always have better HPM and HPS than GHW with all feasible values for SP and CR.

And in practice, it really does feel better on my mana to never use GHW under TW. (Choosing a heal when you don't have TW is another story...) I heard through the grapevine that top-level raiding Shaman are forgoing GHW altogether - while I haven't done any research into this trend, I wouldn't be surprised if they came to the same conclusion I did.

Of course, if I screwed this up somewhere I'd be more than happy to edit/redact as necessary. Thanks for reading.