Dear WHMs: Please use Stoneskin as part of your normal rotation on Warrior tanks, thank you
I had two back to back AK runs with WHM healers, and they were wildly different experiences, enough that I took note of the differences.
Both WHMs were doing a constant stream of Cure 1s, with occasional Cure 2s from freecast procs or as needed, and Regen, as you'd expect.
As far as I could tell, the only difference between the two was that one of the two WHMs was very aggressive about 'capping' me with Stoneskin any time my health peaked, and always after every fight.
The difference was
enormous. The non-stoneskin healer was routinely pulling aggro on adds from the constant cure casting (it didn't help that he would cast heals during the pull, but that's neither here nor there, not counting that as an issue

).
The stoneskin healer however, while he was also steadily healing me, had much longer 'gaps' where he didn't have to do shit. He was dpsing instead. No noticable threat issues on adds.
Because of the shield in combination with regen ticks, I was able to use self healing/mitigation cooldowns to smooth out the incoming damage, and I was often sitting on cooldowns because I didn't need them, being at 75%+ health with regen rolling and not feeling particularly threatened.
I realize on paper Stoneskin is both slower to cast and considerably more mana inefficient to the throughput of raw Cure spam with Cure 2 procs, but the actual impact on the frequency of the damage spikes I was taking was dramatic (ignoring the threat benefits).
This actually makes me wonder if this is why I generally feel more comfortable with SCH healers in dungeon runs, because they have 'built in' damage shields via Adloquium/Succor, and the shields simply work well mechanically with Warrior tanking.
This is purely anecdotal, not backed by extensive parsing, but it tracks with most of my WHM/SCH experiences. It feels like most WHMs don't use Stoneskin as part of their regular rotation, and as a result, the healing feels a lot spikier than when I'm with a SCH (or, apparently, with a WHM regularly using stoneskin).
I probably wouldn't have even noticed it, but I've been paying more attention to healers cast patterns lately since I've been experimenting with using Wrath stacks far more aggressively.
I previously would sit on Wrath and basically only ever drop stacks with Infuriate ready, but now I'm dropping them much more aggressively and it seems to be going fine. Part of that is obviously average gear level rising on the part of everyone involved, but not all of it.
Some math I saw indicated that the overall loss of healing efficiency over the entire time rebuilding Wrath (and not counting Berserk/Vengeance cutting that time) is minimal in a fight where maximal healing throughput is not vital.
But what that means is that I have multiple Inner Beasts to burn in any given fight, which amounts to multiple 'free' Cure/II GCDs that a healer doesn't need to burn on me.
On a WHM that is only spamming Cures, I rarely get the chance to make good use of them due to wasted overhealing, but when I'm getting shielded/regenned, I often take just enough of a slight spike at a time that I can bounce myself back to full or nearly full and the healer doesn't have to do anything.
None of this applies to stuff like HM Primal battles of course, I'm just talking for your daily healing routine.
I'll do some more experimenting with some FC healers and see how it goes.