The theory goes that retribution will do less damage than other classes because it brings greater utility, increasing raid and party damage to offset the lower personal DPS. Does this hold up? I believe that raids should be diverse, with all specs and classes fitting together to create far higher DPS than would be possible with a less diverse raid. I don't think this should be required, fights shouldn't be designed for perfect diversity, but some amount should be required and encouraged. All specs should bring something, either their own damage (or healing or tanking, but I'm more interested in DPS right now), or multipliers for their group.
Five rogues should be inferior to four rogues and an enhancement shaman. That should be inferior to three rogues, the shaman, and a feral druid. They should be inferior to two rogues, the shaman, the druid, and a fury warrior. Arms fits in somewhere, as does ret. Right? Let's look at ret utility.
I'm a big fan of JoW. I love it. I've had it on my paladin and it lets me sustain much higher damage. I've sometimes had it on my shaman. Combined with my pitiful crit chance, water shield, and blessing of wisdom, I did not run out of mana, literally, while chain-casting lightning bolts. According to the ret DPS theorycraft on Elitist Jerks it gives an average of 130 mana/5. Mana spring totem restores 50 mana/5, to one group, but it works for non-DPS as well. For resto this will be 60-some mana/5. I suppose I strayed from my DPS focus. I have to admit ignorance of whether this mana regen from JoW is truly needed for raid DPS or if it only saves mana potions. But it's worth thinking about, and remembering that a tanking paladin could do the same.
JoL is more mixed. I know even less if it is useful since it comes in small amounts and is uncertain. I'm sure it helps, but I don't know that it helps enough to justify a spot.
JotC, improved, gives 3% more crit. Now that is nice. But how nice? For casters that use nukes, it's nice. For physical it is nice. But it doesn't do so much for shadow priests or affliction warlocks. Arms warriors bring 4% more physical damage. JotC isn't the only multiplier to raid DPS.
Sanctity aura, improved, is 2% more damage to the group. That's good. But does it stack up well to others? It varies by the player, but weapons account for around 50% of a melee class' damage output. That leaves 50% coming from gear, specifically AP. An enhancement shaman can increase that by 10%, giving 5% (give or take some fractions) damage to a melee group. I don't know how that multiplier interacts with WF totem which gives additional AP on the extra attack.
But that leads to my next party DPS boost: WF totem. This totem gives a 20% chance for an extra attack on any auto-attack or "on next hit" attack (like cleave). For a 2h user like an arms warrior that is a huge damage increase. It's great for ret as well. It's not as good for a DW class, but it will still be huge. How does this compare to a ret paladin's buffs?
I won't make any claim about whether ret brings enough utility. I think a ret paladin is worth bringing, but I have to admit a bias, since I've played a paladin for a long time and for years have been sympathetic to paladin DPS. I want people to start reconsidering the idea of trading personal DPS for raid utility. It's not that I dislike the idea, I actually like it a lot, I like being group-oriented. My concern is about whether the trade was done properly.
Ret isn't the only DPS that brings damage buffs to others. Feral druids have 5% crit, a heal proc, and mangle isn't totally useless to warriors and rogues (maybe rogues, I don't know if they use bleeds in raids). Moonkin have 5% spell crit. Hunters (these are spread across specs) have ferocious inspiration, improved hunter's mark, trueshot aura, and expose weakness. The list goes on. Warlocks bring some major debuffs, mostly for casters, but they can help melee at a cost. Mages help each other and warlocks sometimes. Rogues, priests, warriors... I can only guess at the damage boost from sunder armor.
Ret does not have a monopoly on party and raid buffs and it certainly has a deficit in personal damage. The utility should be enough to offset the personal shortage, if not, ret needs buffing. I suppose my whole argument can be cleared up, perhaps thrown out, by some theorycraft. Even more importantly though, player experience can invalidate it. If ret paladins are in raids, consistently, and are not considered a drain, do they need changes? Game balance is just about numbers, it's about what we want to do. If we want ret, doesn't that mean it is fine? Or are we just blind to the reality of their utility and damage?