Crit has never been a good tank stat. As a matter of fact, I'm pretty sure it's the single worst secondary stat (aside from spirit) for survival. It doesn't smooth damage, it doesn't allow you to use more useful active mitigation, it does nothing for your EH, and its primary use of generating higher avoidance is even trumped by the widely disregarded parry and dodge stats. Haste is a better survival stat than crit, and we all know how useless that particular stat is. Elusive brew is an awful AM against non-machine gun attacks. As a sidenote, this is exactly why guardian representation is so low in high-end raids, because their main AM is just +dodge. We joke and say that druids don't have AM, they have AP - active praying.
People go crit because it does more damage, pure and simple. Logically, if you're crit-focused right now, you wouldn't want to take a hit to your dps by going with a 2H even if it allows you slightly more uptime on EB. I mean, you could, but that's a bit head-scratch worthy.
Hit will likely generate more EB than crit, up to a certain amount. Simulations required to determine that number, and I'll guestimate it's somewhere between 1500 and 3000 rating over 7.5% with 60% paper doll crit.If you are crit-capped, haste is your best EB generation stat as you well get more of those crit-capped autos.
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Back on track ...
Holy crap.2. Thok's Tail Tip Usually Strength Melee Trinket
Currently 14% on the PTR. Though being a Strength Trinket, the flat crit damage, haste and mastery increase applies to all classes.
For the crit focused player, 75% of their damage comes from crits, 14% more of that = 10.5% damage increase, which is leaps and bounds higher than everything else sans RoRo (the average "good" dps trinket like Renataki is worth ~4% of your total damage). Even if you completely eschewed crit in a mastery favored build you're looking at ~7% more damage.
The haste and mastery boost is also stupid good, if you had around 25,000 rating between those two stats, you're getting a 3500 rating boost from that passive alone, and strength still even gives AP for us. I checked, and there's an intellect version of this as well (where is the agi version???) ... and they aren't mutually exclusive and equippable on the PTR. Well, there's the BIS right there, no further calculations required, for both survival and damage: the INT and STR version of the 14% amplify trinket.
Assuming we can still wear them on live, sigh. Too bad it'll likely be role-restricted soon, but we can hope.