Huh? Might of Ursoc isn't a temp EH boost? Granted it's on a massive cooldown, much longer than Explosive Slam.
Glyph of Frenzied Regen could be taken as a kind of temp EH boost too, since it boosts all healing received by 40%. I don't know if that applies to absorbs as well, though, particularly Tooth & Claw.
EH ensures that we live so we can use FR. For simplicity, we can just say we're about to get hit by a huge damage ability. What can we, as Guardians, do to make sure we aren't one-shot?
I'd say it's more on the active mitigation side of things (or short cooldown abilities) where Guardians don't have a "temporary EH boost" ability, at least something that's guaranteed on-demand. Warriors and paladins can guarantee an EH boost by blocking, DK's have several tools for physical and magical damage reduction on short CD's, monks have Stagger, Guard, and other talents/mechanics to mitigate physical and magical damage... Guardians eat things in the face and heal up afterwards, but we do have Barkskin on a 1min CD (T&C is random and only prevents what I affectionately call "combo attacks" on us, like Dire Call + Triple Horn + Auto-attack).
However, that is class design, and outside of using a major cooldown to take a hit, our only short-CD ability is Barkskin that temporarily boosts our EH. It's partially why I would actually glyph for Survival Instincts on some encounters, because we do lack a method to raise our EH against periodic attacks that have the ability to wreck a tank. Our armor and T&C help mitigate (pun intended) the occurrence of such issues, but sometimes it's not enough or will not directly address the situations where we need that extra EH. If, by design, we either completely avoid or take full hits, then Guardians should likely have more short-term EH-boosting abilities or just a flat-out boost in EH at all times. Boosting our stamina modifiers is the easiest method of doing so.
Well, in pvp at least my thinking is that this makes the MoU (3min cd) + Renewal (3min cd) combo even stronger and it was already like a LoH of sorts. Though it does have a 5min CD when MoU is glyphed.
I guess i'm going to play around with the option of NOT glyphing MoU to gain 2mins and see if the stamina boost on the ptr notes is enough to compensate. And no, i'm not about to do any math because i'm lazy
Basically use MoU to boost your HP, then use Renewal since it's a % of HP based heal, cancel the MoU buff and you're healed to full. Though I never use this on my feral. Only on my other resto/moonkin druid.