Paladin Tanking Mathmetica's

Not really a pug post. At all. Just wanted to make this article from Ferocious Inspiration easy to access. http://www.ferociousinspiration.net/2011/01/prot-paladin-tanking-field-manual.html

Stats for Threat 
Hit capped at 8%, Expertise soft capped at 26. Then stack stamina over strength because not only does more Stamina mean more life, it means a higher top-end for Vengeance. Note: This is only for threat, mitigation should be the first thing you look at.

Hit <> Expertise <> Stamina <> Strength

Stats for Avoidance/Mitigation
With there being no real issue with threat at the moment, avoidance and mitigation to the 102.4% block cap is now the new recommended function. Do not reforge your mastery into hit even if you are not hit capped, you only need 2% hit. The above is a fast and dirty representation of the stat weighting, but there is really much to it.

The block cap is calculated as;

Dodge % + Block % + Parry % + 5%(automatic miss chance by all mobs) = 102.4%

In the game you can run this macro.

/script DEFAULT_CHAT_FRAME:AddMessage("Need 102.4 combat table coverage. Currently at: "..string.format("%.2f", GetDodgeChance()+GetBlockChance()+GetParryChance()+5))

What “combat table coverage” means is that there is a base chance mobs can hit you. If you get your total avoidance/mitigation up to 102.4% “normal hit” drops off of the table meaning the only thing a physical attack can do is be dodged, parried, or blocked, in that order. So if your stats are 20% dodge, 20% parry, and 40% block your percentage would be: 20 + 20 + 40 + 5 = 85% This leaves a 17.4% chance that a mob will get a “normal hit” on you with no reduced damage other than what you get from your armor and talents. This also means that if you have 112.4% avoidance you are wasting stats because the block cap stops at 102.4%. Anything past it does not count for anything unless you get a debuff reducing your chance to dodge/parry/block.

Diminishing returns occurs when you hit a certain percentage of a stat which is called a “soft cap.” At the soft cap and above each point of said stats will be worth less and less. At some point the return on a single point will be worth much less than using that point in another stat. This creates balance and helps to combat stat "stacking".

For the application of protection paladins, dodge and parry now suffer from the same diminishing returns so they are equal in terms of avoidance. If you have a choice put points into the lowest of the two, remembering though that strength also adds attack power and parry so it might make a better choice

For protection paladins this might surprise you but the soft cap against mastery is 10% dodge or Parry. Most of us will have more than this, but above 10% you can reforge dodge and parry into mastery and GAIN mitigation. You even out damage by getting to the 102.4% making it easier on everyone.

Actual percentage where mastery is better than parry. 10.139%
Actual percentage where mastery is better than dodge. 10.5182%

So the couple of questions you need to ask yourself for avoidance and mitigation. What are your current stats? Strength gives parry at the rate of 27% of strength over base level 85 strength.

Mastery<>Dodge/Parry<> Strength

Follow this weighting until block cap is reached.

How They All Unfold
In the end you still want the same three things, just now in a different order, look for block capping THEN worry about your threat stats.

Block cap<>Hit cap<>Expertise cap
Mastery<>Dodge/Parry <> Hit <> Stamina <> Expertise capped 

Never trade hit for expertise. The expertise hard cap is 56 so that gives you plenty to shoot for and replace strength for stamina as your gear puts you above the block cap.