The warr ArP thread is filled with people napkin-mathing ArP wrong, so I wanted to chime in, as I've been watching this pretty close at EJ. Maybe someone with the rating to can cross-post this. I think ArP w/ Grim Toll is going to become our PvP bread and butter.
You cannot get 100% ignore from sunder + shatt + battle + GT proc. You get more like 80%. It just doesn't add like that.
1. Self + Buff ArP (incl mace/stance) is additive.
Debuff ArP is multiplicative (sunder/shatt = -36%).
The combination of the two is "complicated".
I've put that formula at the bottom so you don't have to deal with detail math to read the post.
2. The values where a GT proc brings you to 100% armor ignore is:
No sunder
Zerk = 620 ArP
Battle = 497 ArP
Battle + Mace = 312 ArP
These values are NOT relative to armor of target
With either sunder or shattering throw vs 24k armor (paladin) is:
Zerk = 511 ArP
Battle = 388 ArP
Battle + Mace = 203 ArP
the sundered/shatter values go up vs >24k armor, down at <24k. Takes about ~40 ArP less to cap out vs 5-10k armor
I'm going to shoot for 388 or 497 ArP and use GT. Sunder the target, watch for a GT proc and then run a reck combo vs 0 armor. Yes, you have to wear pve gear to do this. I expect it'll be worth it to hit paladins/DKs like clothies.
497 will be hard to reach in pvp gear until ulduar gear, but once you have an ulduar weapon and a bit of gear, you can probably hit 497 and no longer spend GCD's sundering. Also: bladestorm in 5's at 100% armor ignore (without sunders!) makes me drool.
It's worth noting that Mace = 185 ArP rating, Axe = 230 Crit rating. Axe is much, much better than mace except when the mace is capping your ArP. I don't advise going mace unless you can't get the ArP elsewhere. It's almost as bad as using a lower tier weap.
MATH:
The 3.1 ArP formula is:
Final ArP % = A/(A+B*((1-x)-y*(1-(B/(A+B))*x)))
A = 15232.5, B = target armor#, x = selfbuff ArP, y = debuff ArP
y is multiplicative. Sunder = 20%, ShattThrow = 20%, Sunder + Shatthrow = 36%, sunder + FF = 24%. Sunder + ff + shatt = 39.2%
x is additive. Battle stance = 123 ArP, Mace spec = 185 ArP. It all adds together w/ gear ArP then gets divided by 12.3164 to get you a % for x.
Source is math at
http://elitistjerks.com/f31/t29453-c...evel_80_a/p16/
All of this is assuming the ArP bug gets fixed and that no new major arp changes go in before the patch. I think those are both fair assumptions. If the bug is not fixed, you multiply x by 81% (and ArP sux again).