At level 63, I think I just needed to spam SCK and use Keg Smash and Breath of Fire when available. The healing orbs we generate were healing me for like 20% of my health, and SCK on 3+ mobs usually made at least one, if not more. Guard and Shuffle were overkill, because both self and healer healing is still OP until 80+.
I agree with a lot of what people have said here. There's a lot of fun stuff to juggle to manage while tanking.
Stuns: Suck, these will kill us, since we basically can't do anything and a lot of our mitigation/recovery/avoidance is active. I was doing Mogu'shan vaults, and the only time I really dipped low was when I got chained stunned by one of the early trash packs. I didn't even dip low when the last boss killed the healer at like 10-15% (with 2 DPS already dead from standing in stuff). I'd love to just make some of our defensive abilities (Guard or PB) usable while stunned.
Stagger: Is a great mechanic, but it really doesn't come into its own until you get Purifying Brew very late and can actually do something about it. So the low level comment about Stagger won't be valid when you get higher.
Zen Sphere: Heals me for maybe 10% of my health over 16 seconds at level 89. Meh. I use it sometimes when soloing if I've over-pulled and really need more healing. Lots of better uses for Chi.
Keg Smash: My favorite button. Huge damage, +2 chi, and -10% damage to up to 3 targets.
I'd love to try BrM tanking in raid, but I'm our healing officer, so Main Spec Mistweaver. Maybe on farm content and probably on LFR at some point.