Your numbered questions aren't great, but they're not terrible either. The rest of your post is terrible. Just ask your question without all the personal history, gear updates, random thoughts, and other trivia.
I've been an avid browser of this forum for quite some time, but I've noticed a lack of discussion between the balancing of Spirit/Haste/Mastery/Crit in regards to 4.2 (unless, of course, I'm blind and missed it somewhere). Reason that I ask this being I took a break right as Firelands was introduced and am now coming back to a multitude of new gear/changes/playing styles. Currently, my shaman is well built for 4.1 raids (despite the fact that I never see drops for my set) and is baselined towards the general requirements to handle 10man raids; 2500 spirit minimum, push for 100k mana, enough haste for Riptide and Healing Rain breakpoint, blow the rest in mastery, blah blah. More specifically, I'm pushing about 2700 spirit with Darkmoon Card active (pre-trinket, 3k after popping CD's), about 102k mana unbuffed, I have two haste sets (one with 920 haste if I don't use Wrath of Air, one with 780 haste if I use Wrath of Air) which enable me to hit Riptide and Healing Rain breakpoints if I use them, and the rest is stacked into mastery (off the top of my head, think it was about 47%).
My question is to you shamans that have adjusted your play styles to accomodate Firelands healing (taking into the fact that Mana Tide was unfortunately nerfed, 10man raids are WAY easier to heal, not that they were hard before, but the reduction of incoming damage requires less healing, and crits now hit for 100% extra healing), how have you adjusted your stats? I've been looking at the new gear and planning my aquisition route but there's always that question, "This item, or that item? Spirit with one beneficial stat, or drop the spirit for two beneficial stats?"
1 - Is spirit still worth stacking for MP5 despite the fact that Mana Tide was nerfed to 200%? I have 2700 stacked during combat with pre-Firelands? With the no-brainer choices in gear, I think it's easy to hit 3k spirit without breaking a sweat, but there is some gear without spirit that is just as juicy if you give up the +90-150 spirit.
2 - How much crit chance do you aim for to be worth sacrificing haste/mastery/spirit for more crit? In my opinion, if you can hit 20-25%, I think that should be enough but is it enough to pass up the extra MP5 during combat?
3 - After you have enough spirit and haste, your only option left is to reforge into crit or mastery... how do you balance those two? Obviously, if you're raiding Cataclysm, you can lay off the mastery and vice versa on Firelands, but how did you balance it?
I think what I'm going to TRY to aim for (albeit I don't know if achieveable), is to hit these personal soft-caps:
3,000 Spirit (for enough MP5 during Firelands combat)
916 Haste Rating (for enough haste to hit Riptide breakpoint without Wrath of Air)
15%-20% Crit Rating (I can't imagine any more than that is worth sacrificing other stats for)
Dump the rest into Mastery since I'll be watching health drops more in Firelands than Cataclysm
You're the experts, and I'm just the idiot asking for some tips.