Stam (and armor) will likely be identical between tank and dps plate of the same item level, so we can ignore it when comparing pieces. At least, that's how it is on live, and is my assumption for MoP.

In terms of reforging mastery to parry on my dodge/mastery tank example, here's how it would turn out:

100 dodge = 185.72
60 mastery = 26.076
40 parry = 74.288
total = 286.084

So the dodge/mastery "tank" piece, reforged, is 29.1% better than the crit/hit "dps" piece (also reforged), but only 0.43% better than the haste/hit piece. Factor in diminishing returns on dodge/parry, and the haste/hit piece would likely be better.

It would be dependent upon Encounter mechanics. For example, in a fight like Heroic Yor'shaj the damage you would be taking from the DoT will far exceed any blockable damage from the boss itself. You could add in the extra critical effect if Sacred Shield is taken as well.

Blizzard has stated before that their philosophy for determining encounter mechanics is based on the presently available player mechanics. Blizzard accepting WoG as a Tank Cooldown for Paladins would also ensure that they intend for it to be used.

There's nothing wrong with WoG being a situational ability (not that you're saying there is, but there does appear to be a sub-text of disapproval going on here). Everything is situational, really, or will be once the numbers are crunched thoroughly enough to figure out what ability is optimal in which situation. Its pretty much impossible to balance abilities such that you'd literally be indifferent to which one to use in a situation, and even if it were somehow possible, it would be pretty poor game design to create conflicting abilities. So, whether WoG is rarely used will be dependent on how rare are the situations in which its the optimal use of HoPo.

Which ability to use in which situation does indeed seem like it will be pretty clear. If the boss is meleeing you and its melee isn't absolutely trivial, then you use SotR. If there's a break in the incoming melee (boss is out of melee range for some reason, or goes into a cast-only mode, or its a tank swap/BQL thing) then switching over to WoG could be a reasonable choice (to help out with the healing) though if its a burn phase, sticking with SotR would probably be valid, depending on how the mechanics and your raid's capabilities shake out. Of course, if the boss is up flying around and out of melee, you could WoG, but you'd also want to make sure you'll have have enough HoPo to ensure a SotR as soon as it lands.

We don't know any of this stuff yet, so while it seems quite likely SotR will be the "go to" HoPo use, its impossible to say how often we will end up WoGing. In Patch-style fight, sure, pretty close to never. With Yor'sahj, I could see sticking with SotR since you'd probably want to keep doing damage to the boss while he's calling the blobs, and doing damage to the adds/blocking their attacks isn't a bad thing either, but I could also see an argument for using WoG a good bit as well(your damage against the adds is probably pretty trivial, and I doubt they hit hard enough to make the block more valuable than the WoG).

Edit - With regard to stat weights, nice work Theck! An added advantage, of course, with going with the dps gear is that you'd probably do a fair bit more damage with a bunch of hit/haste pieces (even reforged to dodge/parry). Certainly your first priority is staying alive, and it sounds like threat will be trivial to maintain, but tank dps still has value. If you can get 99% of the survivability with dps pieces and up your dps by 20% or whatever, that seems like an attractive choice (assuming the various assumptions we're working with hold). I'll be a little surprised if they let Mastery go live this awful.

Per MMO Champion today, regarding the new beta build (15650):

Protection:

Sanctuary now decreases damage taken by 15%, up from 10%.
Shield of the Righteous now reduces the physical damage you take by 30% instead of increasing your block chance.

The tool tip for SotR: Instantly slam the target with your shield, causing 4,063 Holy damage, reducing the physical damage you take by 30% for 3 sec, and causing Bastion of Glory.


The Sanctuary change brings us up to the base damage reduction of warriors.

The guaranteed physical damage reduction (even from unblockable sources, apparently) is nice. Three seconds of damage reduction from SotR seems pretty low. Basically one boss swing or one telegraphed Big Attack. If there are any bosses with long swing timers (Baleroc fire sword, for example), you'd actually have to time your usage correctly to even get one "block".