This is an encounter where Retribution Paladins can flourish provided the raid is coordinated. Some raids will need melee to free Flash Frozen targets, which can be crippling to DPS. That's fine. We can do a better job than most in freeing frozen NPCs because of burst damage, although damage contribution overall will be lower. It's also somewhat more difficult to take advantage of all the buffs from the NPCs because Retribution Paladins need to stay within melee range of the Hodir, so it's easy to miss out on Starlight. The good news is that any melee affected by Storm Cloud can easily pass it on to other melee. We'll need to keep moving, anyway, to prevent Biting Cold from stacking.
Hodir is basically a glorified DPS check, if a very fun one. The only way to beat this encounter is to take full advantage of every buff available, which requires positioning and coordination. The tank is tasked with positioning Hodir near Starlight, for example, and any player with Storm Cloud is advised to run to the melee group. If all things fall into place, Retribution Paladins can have their DPS shoot through the roof. We are also less susceptible to Freeze, as it can be dispelled and Hand of Freedom can break it. Make sure to turn on projected textures in order to better see spells on the ground.
Consider this a free pass. Retribution Paladins in this encounter don't have to do much at all, and the biggest feature of this encounter -- Aura of Despair -- is offset by the a greatly improved version of Judgements of the Wise which also cripples healing by 75% (so don't bother). This allows us to concentrate on doing one thing: keep on hitting the boss. It is also important to keep up a /range check set to 15 yards to show players that can be affected by the siphon effect of Mark of the Faceless. It is supremely important to move out of range of anyone when affected by the leeching debuff as each tick per second heals General Vezax for a whopping 100k. Fortunately, he also has a very large hit box, allowing more than a few melee to position themselves around him without having anyone else within 15 yards.
Another important reminder is that Hammer of Justice can interrupt Searing Flames, so be ready to interrupt at a moment's notice if one of your assigned interrupters is on cooldown. Do not expect to excel in DPS during this fight, as the fight is designed for endurance rather than DPS. The Shadow Crash residue is also designed to improve caster DPS specifically, so the burden is theirs to bring Vezax down before he enrages. This is perhaps the easiest fight for melee in all of Ulduar but arguably the hardest for healers.
This is a rather complex fight and there is no one way to optimize DPS, particularly with the help of all four Keepers. First off, it's going to be difficult for melee to perform optimally against the Guardians as they explode upon death and must be dragged near Sara. This basically rules out sticking to the mobs, and depending on the raid strategy (which might involve tanking and killing them near Sara to begin with), this could mean very little participation for melee DPS. This is where being a hybrid class becomes supremely useful. While it isn't possible to remove Dominate Mind on others (targets are considered unfriendly), it's possible to remove it though Divine Shield. Players should use this phase to heal, cast Sacred Shield, and generally assist the raid when unable to DPS a Guardian directly. The best aura to use throughout this encounter is Shadow Resistance Aura. Needless to say, avoid the clouds at all costs.
Phase 2 becomes even more critical for Retribution Paladins. One word: Cleanse. Because Paladins can remove three of the four types of debuffs during this phase, it is of utmost importance to prioritize dispels. More than DPS, this is a Retribution Paladins best contribution for the Yogg-Saron fight. Obviously, players are still called upon to destroy tentacles throughout this part, but between getting an extra Crusader Strike in or Cleansing a raid member, the latter takes precedence.
If sent into the brain realm, be mindful of the Laughing Skulls. Melee players should be familiar with facing issues by this time and should have no problem maneuvering through this encounter. Here it is pure DPS and players can go full bore at Yogg-Saron's brain... Avenging Wrath, potions, etc. The same can be done outside, when Yogg-Saron is at what is considered his "weakened" state.
Once you manage to get to Phase 3, it becomes incredibly simple by comparison as it is generally a DPS check. While melee can switch to Immortal Guardians during this phase, they're probably best left to keep on hitting Yogg-Saron while trying to avoid insanity. When Yogg-Saron channels Lunatic Gaze, simply turn about face and optinally attack a nearby Immortal Guardian. Rinse, repeat, profit.
No idea. I'll let you know if we ever get there.
Ulduar is an extremely fun raid, perhaps one of the most interesting dungeons that Blizzard has ever designed. The encounters change drastically in Hard Modes, and this guide only covers the easy modes. As "easy" as Ulduar has been criticized as being, it brings a lot of challenges for players, even ones who play "ez-mode" specs such as Retribution. There's a lot of room to optimize one's game, and ultimately, a lot of room to enjoy the raid. Good luck!