I usually spec into intensity on the resto tree (there's no other moonkin talents that I truly want usually, especially if I skip eclipse) which causes something like 50% of your mana regen to continue while casting.

I knew that haste reduces the global cooldown, but Nature's Grace isn't haste. I'm certainly not saying you're wrong, because I just don't know, but has anyone confirmed that Nature's Grace is a haste mechanic and not something that is supposed to be used for starfire instead? I can see them intending it to be used during wrath spam where it procs, you cast one additional errant wrath (due to reaction timing) and still have time to get one starfire in before the 3 seconds is up.

I'm 100% sure for solo play moonkin gear is better than resto for moonkins in both PvP and PvE. For multiboxing, I'm about 75% sure moonkin gear is still better, though I'm not sure how much better. All these procs on crit are impossible to manage.