First off, thanks to anyone who's been linking me on their own blogs, I appreciate it. I hope what I write here is at the very least informative on the ins and outs of Retribution.
Next, I wanted to follow up on my talent guide posts by breaking down the types of gear a Retribution Paladin straps on when he dives headlong into battle. There is a lot of misinformation flying around about how a Ret Paladin gears with regards to several of the "secondary" stats (armor penetration, haste, spell damage, etc). In no particular order, these are the stats that will, one way or another, boost a Ret Paladin's damage:
Now, what I did not say is how much each affects your damage. The list above is not in order of effectiveness by any means. What follows is an evaluation from an Alliance Ret Paladin's view - Blood Elves have different priorities based upon the interaction of Seal of Blood with haste. Let's look at the base statistics first.
Melee crit rating
Melee hit rating
Spell hit rating
Your base stats are the 5 that appear in the default left frame on your character's paper doll in game. They are, in order - Strength, Agility, Stamina, Intellect, & Spirit. Not all of these stats have a direct effect on your damage. Intellect increases your mana pool, but does not amplify how hard you hit or increase your longevity. Spirit only functions in combat if you have special talents or stop using abilities for at least five seconds. Stamina increases your HP, but doesn't make your melee stats any bigger or smaller. Strength and Agility are what we are concerned with here. Strength is arguably a Ret Paladin's best stat. Every point of strength is equal to 2 points of attack power, base. Divine Strength amplifies that conversion to 2.2 AP per strength. Add in Blessing of Kings, and you get 2.42 AP per strength, which is one of the best stat conversions achievable in game. Your strength is your best scaling statistic - never forget that. If you have a choice of 10 strength or 20 AP, you will get much more out of the strength. Agility increased dodge and melee crit along with armor - what we like about agility is the melee crit increase. After all, crits stack up our Vengeance, and we most likely are using the Relentless Earthstorm Diamond in our helm's meta socket (you did get a helm with a meta, right? Good!) to increase the damage our crits do. Crit is one of our next best scaling stats, so agility is never a bad thing to have.
The Secondary Stats
After the base statistics, there are a number of other stats that you can find on gear that will amplify your damage. First is melee hit rating, which eliminates the chance for your attacks to miss. As mentioned in previous posts, you need 9% melee hit from gear and talents combined to eliminate miss chance when attacking a raid boss. This is one of the top priorities when choosing gear - if at all possible, try to stay at, just above, or just slightly below the hit cap. A missed attack is a lot of damage opportunity lost - if an attack doesn't hit, it can't proc Seal of Command.
Melee crit rating is also a very useful stat. It's not something we stack with reckless abandon like a Fury Warrior, but it's good to have a healthy amount, somewhere in the 25-35% range. Crits stack Vengeance, and our very large 2H swings can crit for quite a bit.
Melee haste is a debatable stat. On the one hand, it is not very useful to the starting ret paladin, Seal of Command does not proc more if you attack faster. At the tier 4 and tier 5 levels, you won't find very much gear with haste anyway. However, when your regular auto-attacks start getting large enough, haste starts to look very appealing, even though it does not interact with Seal of Command. At a certain point, adding 20 more AP or attacking 1% faster has the scale tipped in the extra attack's favor, since your attacks will average in the 1.5-3k range. Add in the additional chance to proc Judgment of Wisdom since you will be attacking more, and you've got the makings of a very favorable statistic. So, contrary to a lot of opinions out there, melee haste is not the devil. Welcome it on your gear in the higher end of progression, it helps.
Armor penetration is another debatable stat. It does not affect Seal of Command, just like haste. However, it does affect 75% of your damage - auto-attack and Crusader Strike. The rub is that it doesn't provide good returns unless you stack a bunch of it and have armor reducing debuffs on the target. So, unless you have a bit of gear with ArP on it, and your raid is throwing Faerie Fire (Feral), Sunder Armor x5 or Imp. Expose Armor, Curse of Recklessness, and all that jazz onto the target, you might be better served with other stats. HOWEVER, if you've got it, stack it - it's just not something you want to go out of your way to stack.
Attack power is generally inferior to strength. But, there are some pieces of hunter mail or rogue leather that have gobs of AP, more AP than you could get from an equivalent plate piece with strength on it. It's worth looking in to.
Spell hit rating does increase your DPS. Judgement of Command functions as a spell for hit mechanics. However, JoComm is such a small part of your total DPS, it'd be silly to go out of your way to stack this stat. Ignore it.
Spell damage, contrary to what most people say, does increase your damage. JoComm, Consecration, and Exorcism - staples in your rotation - all scale with spell damage and not any melee statistic. Seal of Command also gets a boost from spell damage. This is why [Darkmoon Card: Crusade] is a great trinket for Ret Paladins - we benefit from both the AP increase and the spell damage boost. However, an equal amount of strength or crit will affect a larger portion of your overall damage than a serving of spell damage. It's not a stat a Ret Paladin will stack for maximum damage output. This is why our tier sets had their spell damage moved directly into strength.
Expertise eliminates the enemy's chance to dodge. This is a very powerful stat, as is one of the most important statistics to have. Just as with hit & miss, a dodged attack is a lot of damage lost. The expertise "cap" is 104 expertise rating for non-humans, and about 84 for humans using a mace or sword due to racials. Oftentimes any expertise you can get your hands on is worth equipping.
Tying it all together
So what stat are you aiming for? Oftentimes you want to go for gear with strength, crit, and melee hit first, and take what you can in terms of Expertise, ArP, melee haste, AP, and agility. Spell damage should be avoided, as you can most likely find a piece of gear for any slot that will provide more damage from AP/strength/crit than an equivalent spell damage piece. You also want to keep your AP and crit numbers in balance. Having a 35% crit rate isn't very helpful if you have only 1200 AP. Likewise, having 2000 AP is great, but not if it's at the expense of having a woeful 18% crit rate. Using a spreadsheet or the Rawr application to make informed gear decisions about what's best for you at your gear level and considering what's available is highly recommended. If all else fails, and you're completely lost, you can't go wrong stacking strength and crit with a 95+ hit rating and Precision.