When does BV > Armour?

I was trying to figure out if I should swap out 70 BV (what I normally get from Shield Specialization with my current gear) for 350 Armor (Improved Devotion) and I came up with this comparison.

Comparison against lvl 73.
(used formula

Imp Devotion Aura's pretty terrible imo.
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A Hero desires a Sword, and a Sword desires Truth.

Care to elaborate? I used to think so, but 350 armour is not a bad buff.

Keep in mind it is vs Redoubt which is a small % chance to add some % to block for a few seconds. If HS is up, it is an utter waste of 5 talent points. Armour always works (for melee).
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There's no straight equivalence between armor and BV because BV is static whereas armor is a %, so the harder a mob hits the more weight armor gets, and the less hard it hits the more weight BV gets. Shield spec also scales with your gear, whereas Imp Dev Aura does not....you're not going to be tanking anything that regularly melees for 8k with 233 base BV (corresponding to the 70 BV you said you were getting from shield spec).
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Additionally, Redoubt is a good talent for AoE tanking.
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Good points Dorvan, but I don't think i need to worry about gear scaling at this point. They aren't coming fast'n'furious as we are just getting to Vashj and Kael is a bit off and if I get more T5 pieces I'll just respec if it makes sense at the time. Seems odd to use a spec that is future-proofed (ie. scaling) when I can just respec on a whim. At what base block value is it worth having the extra 30% at?

I do see your point that 20k may be a bit strong for a base number to calculate off of but wouldn't the relative difference for lesser damage be the same unless the dmg value is sufficiently small?

Has anyone graphed any of this?
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