One thing I would like to point out regarding glyphs: Water Shield is mandatory with the current gear level and you would in my opinion want to switch it with ES if you are raiding 25man or ELW if it is 10man.
Regarding crit vs. haste, well it is quite a lot about how you play your class and sorry to say - But you cannot use theory crafting in as wide degree to healing as for damage. Sure, you need a shit load to reach the next tick, but it still is a constantly HPS output increase whereas crit is, well, an unstable HPS increase since the majority of crits (when we talk HS / GHW) in raids will be overhealing (unless you sit as sole person on a tank which should never happen) and yes crit does increase you mana regn. but following that logic you would want Water Shield glyph in the first place so?
Ancestral Swiftness - ofc. you do not NEED it, but it is an amazing utility and will save your arsh a lot of times + reduce the damage with e.g. damage debuffs on the raid if you are fast .
And good job with making a guide =)