Are our savage defense uptimes exceptionally high in practice, or in theory? Despite looking at the equations used in your spreadsheet and agreeing with the the implementation, I'm really not seeing it translate to actual encounters. Unfortunately, I've yet to find any good automatic way to parse savage defense uptime from logs - would have to script something that looks for savage defense aura fading combined with a recent hit that had a portion of it absorbed. That said, it's not terribly difficult to manually parse some fights with WoL for accurate small data set results, or to estimate savage defense uptime by taking the total amount absorbed and dividing by an 'average' savage defense value in order to get a guesstimate for number of savage defense absorbs.
This is really tricky and hard to do because the combat log does not separate absorbs out for us, merely it lumps them all together and gives us a sum. We would have to parse each log for all AP buffs, current Vengeance levels, the stats of the Druid at the time, and note the uptime.
Of course the spreadsheet is in theory, it is based on averages. Even a very long fight by most raiders' standards will not produce enough events to produce a similar result to the spreadsheet consistently, such is the nature of RNG. But we all know that in the long term, gearing towards a general trend is best, while making sure you are capable of dealing with the absolute worst possible scenario, how often or not it occurs.
For both small data sets as well as the more 'guesstimate' of a method, I'm typically seeing 30-40% of melee hits being absorbed by savage defense on a boss with the debuffed 1.8 swing timer that Bliz seems to like. That's actually why savage defense is actually somewhat balanced, seeing as how 40k hits at that speed + magic damage is enough to cap out vengeance and give 20k+ absorbs. But even at that kinda normal mode boss damage output, total 'mitigation' numbers end up pretty close compared to a paladin tank only because of the marked difference in avoidance - blocking 12k two thirds of the time is already slightly more effective than blocking 20k one third of the time (and that ignores the fact that savage defense absorb amounts are quite variable.)
A 1.8 swing will have a very different effect on a Druid's SD uptime than a 2.4 swing. I can rerun the numbers easily with a varied swing to see how it works. It is also another reason perhaps why Block is 'superior' but I hesitate to use such a word since again, Mastery isn't the only thing we have going for us as Tanks to mitigate damage.
I'll probably do this when I do the Stam vs Agi comparison for the trolls.
Anyway, for now I only feel slightly more squishy than our paladin tank, which I don't mind all too much given that we each have different strengths. Bears have a marked advantage in avoidance, whereas paladins win out on more consistent damage. Heh, it reminds me so much of BC, especially since they essentially brought back crushing blows on every attack that's not blocked =P Oh, and yay for an actual explanation of the vengeance cap - it'd been bugging me for a few days now.
Our Avoidance certainly helps a lot, and that's fine. Our Stance modifier is also different from other Tanks. Our Armor is different as well.
I know that my Healers stick the WEAKER Healers with me on Nefarian when they are split between healing me while I tank Nef and healing our Warrior while he tanks Ony. We've swapped it up before the but the weaker ones always come with me because I'm the easier one to heal, and consistently, according to them. Obviously completely anecdotal but there you have it, I'm either getting really lucky or I'm doing something sorta right.