Since this tier seems to have a lot of strictly physical (or unresistible magic) fights, and prismatic is out of the loop on half the content, are we better off using the armor elixir or the stamina scroll? Essentially it is 900 armor vs 150 stamina. Number are fairly close and I am wondering what everyone thinks.
I'd use the stamina scroll. 900 armor is such a pathetically unnoticeable amount of actual damage reduction. It takes about 45000 armor to get from 65% (about 42000 armor) to the cap at 75% (~97000), so you don't really need a calculator to see how relatively meaningless 900 armor is compared to the 2100 life that 150 stamina gives you (before spec bonuses and buffs).
Note I am not saying that armor is a useless stat, it is just that there are much more noticeable ways to improve your survivability.
That's a 1.2% physical damage decrease in this example. I'd have to stack a bunch of avoidance or mitigation rating to get a similar result. 3370 extra hitpoints (raidbuffed including the mixology bonus) on the other hand increases my healthpool (~ 205k buffed) by about 1.6%. For 175k tanks it's a 2% buff and for 275k tanks it's a 1.25% increase. If you want more leeway for your healers, stamina should come out ahead. If you're concerned about the incoming melee damage and that decrease saves your healer some mana armor might comes out ahead. But in general it's rather hard to see that benefit from just one change, your healers will still tend to use their heal of choice and it's just overheal, we'd need to look at that in a larger picture (just like 1 mastery gem vs 1 stamina gem is a give or take of almost nothing while going on the mastery route rather than being a mana sponge will have a noticeable impact on your healers blue bars).