Stats of Value: Crit, Resil, Block Value, Armor Reduction, Stamina
Armor: Which pieces do you sub out the pvp gear for PVE gear with high block value? You've gotta get the 4/5 pvp set bonus, and to be honest, it seems like the S3 pvp gear outweighs the PVE block value gear with the exception of shield choices.
Enchants: I'd assume that you'd go for an executioner enchant, cobra leg enchant, and CH head enchant. Anything else that's major?
Trinket: Insignia + Auto-Blocker... rawr.
Q3) What's the value of strength/AP to a prot pvp warrior?
A build like that, while fun for world PVP and battlegrounds, I think would be unwise in arenas. You're never going to be targeted, so your rage generation will be horrible, and your damage output even worse.
If you really want to try to do arenas with a lot of points in Prot, I'd suggest something like 0/31/30. A spec like this would have you spending most of your time in battle stance using a 1h weapon + shield. You'll want to focus a lot on stamina and AP, with a reasonable amount of crit.
Since Bloodthirst damage is based on AP rather than weapon damage or block value, it will allow you to do much more DPS than taking Shield Slam. It's still not insane DPS, but that isn't the strength of this build. Its strength is being able to lock down a caster for LONG periods of time, while still putting out some reasonable damage. Shied bash, concussion blow, fear, intercept, spell reflect. Consider yourself the worlds biggest thorn, because I can't imagine anything being more frustrating to a caster.
I realize this isn't exactly what you asked for, but I think you'll find it to be more effective while still being different and fun.
The build features second wind, MS, mace stuns, Deathwish, imp intercept, conc and bash. It even leverages the heavy crit gear via deep wounds/impale. The build lacks piercing howl, which I think is a big deal.
I was looking more for a build that uses shield slam = )