Please don't quote-split. It makes your post longer than it needs to be.
Originally Posted by Chuupag
I don't think your numbers remain valid once you've made so many assumptions. Base crit at this gear level is up around 13%, and even in people avoiding crit the lowest I've seen inspecting other shamans and armory-ing is 14%. That number for all intents and purposes should be considered the 'base' when making calculations such as this.
The assumptions are made since base crit should be irrelevant to the ratio of HPS/Stat vs MP5/Stat. I've redone the calculations with my own gear (7107 Intellect, 10042 SP, no buffs other than WoA, 1268 Haste, 1490 Crit, Burning meta):
+100 Haste is 161.46 HPS. +100 Crit is 108.25 HPS. The difference is 53.21 HPS. The MP5 difference is 40.48 MP5, which at 7107 INT translates to 57-58 Spirit. Both Crit and Haste translate to > 1 HPS per secondary stat, so ~57.5 spirit reforged is necessarily better than 53.21 HPS.
I want to add that while Haste looks better than Crit here by quite a bit throughput-wise, this represents nearly best case scenario since the timeframe is 1 "rotation" while if projected into infinity in a normal fight Haste runs into the problem that 2 out of the 3 spells are bound by cooldowns. This is why my first reaction when reading Jessamy's comment ("Every time I crunch the numbers I find that haste, crit, and mastery all improve healing throughput by similar amounts.") is that it's true, but Crit has the additional benefit of being a regen stat and via the magic of reforging you can convert regen into further throughput.
I'm also getting a different number than you for your spirit to mp5 conversion.
This is true. 7k Intellect is the number for the 31.58->45 Spirit conversion, while at 8k Intellect the conversion is to 42 Spirit. Considering that the HPS difference is 23.4 in the example, however, I think the amount of Intellect needed to totally inflate the value of Spirit to where it's equivalent is unattainable. In the interest of being complete I input 12k Intellect, into my spreadsheet, and the Spirit equivalent was 35 Spirit, in exchange for 29.3 HPS.
I also think your consideration of stats on TC is in error. ... Your numbers may vary, but this small number shows that it would take over 100 crits to beat 1 extra cast.
I think you arrived at your conclusion in what is somewhat of a roundabout way. Haste translates directly into extra casts, where 1% extra haste will give you 1 extra cast every 100. It is somewhat muddied by the fact that Haste is multiplicative, but we can agree that it's slightly less than 100 casts. If we say that Crit takes over 100 casts to do so, that is right in line with my consideration that for TC, Haste > Crit >>> Mastery.