At first I geared this way. Then I geared a different way. Here's how I feel about it.
The words "I feel" in your post are a red flag. We're not about feelings here, we're about trying to figure out what is the provably best practice.
Initially I focused on stacking mastery, since it seemed intuitive that at all times there was a health deficit, and in some fights you can never hope to top people off again.
I changed my focus to haste recently to give it a try after noticing that Riptide is easily my highest performing heal, at least in 5 mans, which isn't affected by mastery. I literally halved my mastery from 1200 to 500 and I only lost 5% increased healing, and the full effect of that 5% only applies to targets nearly dead. This seems to me to be the underlying flaw to mastery that you gain so little by stacking it, and even then the benefits are diminished by being an effective healer in the first place.
By stacking haste I shaved another 0.3s off my HW/CH/etc and added 2 more ticks to my Riptides. Basically I'm focusing solely on Spirit/Haste gear, and when I feel I have enough regeneration I'll reforge the spirit to crit, which after refocusing from mastery to haste, my crit actually went up fortunately while reitemizing.
My crit has already reached 20% in 5 mans without even putting much effort in focusing on it, so I feel it doesn't need to be our greatest priority, especially when it's one of those mechanics that is only "sometimes" there, especially in the beginning of an expansion.