I was minding what is actually the "best" opening as a SMF? With CS or with BT? Because if we start with BT we are losing the armor pen. debuff and we have a chance to overwrite a bloodsurge proc, and in the middle rotation if we had a BT incoming and a CS up, I can delay a BT to put CS or just BT and then CS and BT again (with the chance of overwrite the bloodsurge proc)? Any experienced warrior can say to me what will be the optimal choice?

Stamina is generally only taken over Mastery in bleeding-edge progression situations where a tank's guild feels more comfortable running with at least one tank with a massive health pool who is less likely to die during a burst of high damage while the guild is learning the fight(s). For standard raiding, avoidance / mitigation is what you should be gearing, gemming, and enchanting.

The short version: get as much Mastery as you can, and then grab as much Parry / Dodge as you can afterward.

This is actually the exact opposite of what you should do. Mastery comes first, always, over everything else, and then you crank up doge and parry to whatever you can, while keeping parry slightly higher (depending on your DRs) due to Hold the Line procs.

I don't think you understood what he was saying or even what he was replying to. His answer was in the context of the value of stats after you've hit the CTC. Mastery is only valued "first, always, over everything else" when you're short of the cap since it covers it most effectively up until that point. Once you are at it however, blocking is obviously inferior to completely avoiding an attack. So he was absolutely correct. You get as much dodge/parry as you possibly can while still leaving enough in mastery to cover the remainder of the combat table.

If you're looking at [Essence of the Eternal Flame] from strictly an avoidance standpoint, you're better off leaving it alone. 1277 Strength equates to ~1.45% Parry Rating after DR. And even though Mastery is technically superior to Dodge (until reaching CTC, anyway), the on-use from [Stay of Execution] is still superior.

EDIT: Revised my formulas to include the change to Base Parry from Strength, which is now 27%, up from 25%. [Stay of Execution] is still the superior trinket.

You can also reforge the dodge into mastery to get slightly better CTC if you're below the cap.

There's no amount of Mastery available in the game that will let you hit the Critical Block cap, so the evaluation is do you want to stack Critical Block, which is roughly a 45% relative damage reduction compared to a normal block, with no diminishing returns on it, or do you want to stack avoidance, which has steep diminishing returns. The answer is always the former for any situation you can think of regarding physical damage.

Question in quick form: My self heals are more effective than they should be, why?

Full question with numbers:

I'm scratching my head over this one.

Examine the following:

HP: 127117
Enraged regeneration (3% of max health) heals me for 4500 per tick instead of 3814
VRush (20% of max health) heals me for 29999-30000 instead of 25423
Bandages, which should be 4375 per tick, instead heal me for 5162-5163

There is a talent that improves self healing but I have not specced into it. I tried the following:
1) Actually -taking- the talent. This improved my self healing by an additional 1.2*1.06% as expected, on top of the mystery bonus. VRush healed me for 38159 (which is indeed 1.2*1.06% more than 30k), and the ER healing also improved as expected
2) Resetting all talents. The mystery healing bonus remained

I suspected my gear (hey, you never know), so I went naked.
HP: 47625
Enraged regeneration: 1868 per tick (which is more than the expected 3% of max, 1429)
Bandages are still healing for 5162-5163

I then switched over to my tank spec to continue my experimenting. My taking spec DOES have the 1.2*1.06% self healing talent. Bandages are healing for 5472-5473, other self-healing abilities are still healing me for more than the expected amount on top of the talent bonus.

Glyphs are surely not at the cause since none of them have any impact on health or healing.

Using a bandage on someone else healed them for 4375 per tick. Worth a shot.

I am extremely puzzled. Where is this bonus healing % coming from?

Lol. As soon as I saw this post I had a hunch your extra healing% taken was going to be exactly 18%, and so it was. We have a hunter in our guild that has taken 18% extra healing since we noticed it sometime during ICC progression. We have never found an explanation for it. He hasn't lost it yet even after going through a race change, however many dozens of talent resets/gear changes, and a new expansion even. It appears to be a permanent bug that affects some characters for some inexplicable reason. Thank your lucky stars, since it's an extremely valuable bug to be afflicted with, especially if you tank regularly.

Edit: Err, in case it wasn't clear, it won't just be your self-healing that's affected. Any heal on you from anyone is affected.

Sorry, the answer is the latter. It is literally impossible to run enough avoidance rating for the DRs on avoidance to ever make avoidance less valuable than mastery that only contributes to crit block. As you stack avoidance into the DRs, mastery for crit block is devalued just as much as dodge/parry since you're pushing block off the table and therefore reducing the value of converting blocks to crit blocks. Past full CTC, dodge/parry will always be superior to mastery, regardless of how high the DRs run.

You don't seem to realize the way a two roll system works.

First roll = whether or not you block
Second roll = whether that block becomes a critical block

Once you reach 102.4% your mastery is no longer increasing the chance of your first roll, and is only increasing the value of the second roll. Effectively you only gain half of your mastery bonus past 102.4% except during shield block. At this point mastery's marginal gains are less than that of dodge or parry. Which was explained above, by saying that the relative worth of dodge and parry is higher than mastery past 102.4%.

TL;DR