Cool breakdown, you might want to add Pillars of Might though. They are BiS for EHP.
Also, you don't really provide a reason for getting the trinket and you neglect these two items:
Unidentifiable Organ - Item - World of Warcraft
and the heroic version: Unidentifiable Organ - Item - World of Warcraft
And the second item:Sindragosa's Flawless Fang - Item - World of Warcraft and heroic version Sindragosa's Flawless Fang - Item - World of Warcraft
The unidentifiable organ is leaps and bounds better at full stacks, which will probably have a very high uptime, and will be better than the badge trinket at just 1 or 2 stacks (the non-heroic version). The heroic version is on par with the skeleton key with no stacks.
The Sindragosa's Flawless Fang is also a very exceptional trinket that will probably find many uses, and is arguably better than the badge trinket for most scenarios.
I also believe that the 258 Jug's Vit is superior to the skeleton key because of the on use. I think overall if you're using glyph of indom or dual Jug's, the stat upgrade from the skeleton key is small enough that it doesn't warrant acquisition until there is nothing else you can spend your badges on.
As far as the helm goes, you also neglected Broken Ram Skull Helm - Item - World of Warcraft, which is on par with the T10 helm.
Other than that, very good guide. I really like the breakdown of both EHP and total DR.
You also might add the stipulation that it depends on your current gear. For example, since I have the 258 LJ cloak, the badge cloak is a smaller upgrade for me than the gloves, chest, and belt.