Pallies biggest weakness in a raiding environment is going OOM and not having a steady white damage rotation. Rogues and Warriors do over 50%, sometimes 60% of their damage from strictly white hits. This means auto attacks. They get this damage from flurry and slice and dice, both of which increase attack speed. Rogues use a 1-2pt Slice and Dice open initially which propels their damage output, especially in 3pc T2 where your poisons see a significant increase (including a few points into Assassination for improved poisons). Warriors use attack speed for rage generation which allows them to utilize their toolkit of specials, the first of which is generally the hard-hitting Bloodthirst, followed up by Whirlwind (in Vanilla, only your mainhand does WW, not your offhand), and if you have a ton of rage, either Heroic Strike to dump rage, or cleave if you are threat capping (because it does significantly less threat). As you get more geared on a Warrior, you inevitably proc flurry almost every white hit due to your crit chance, thus negating the need to focus on dancing to battle to utilize improved overpower to generate flurry stacks.
Paladins do not have this luxury. Their toolkit is entirely composed around burst yellows in Seal of Command, and judging. Consecration is also useful, but not until you have a lot of spell power, typically in T2.5. So, for the first 2 raid tiers, you are geared more like a Warrior to make those specials hit very hard. This does make threat an issue on some trash pulls. In 5 mans it definitely causes issues, in conjunction with consecration hitting an unlimited number of mobs. Warriors simply have a hard time with threat against a Ret who runs in, drops consecrate, and unloads a string of SoC crits and judges a target. Rets that do this also run oom and are drinking between almost every pull. The key is finding a healthy balance, which unfortunately, significantly reduces your potential damage output. Most Fury Warriors don’t care because their damage is going to close out mobs and put them into kill position. Rogues don’t care because they can gouge, feint, vanish, blind, and maneuver the threat in their favor, all the while doing incredible DPS at every stage.
Onto PvP; Ret is a one-trick pony. But you still do have an amazing toolkit in bigger fights. Most good premades are going to take a Warrior versus a Paladin who freedoms himself and then promptly gets sheeped, forcing a bubble. If you want to end up in a good premade as Ret, you are far, far better off, just healing. You are open to counterspells, chain CC, mana burn, among others. But they are still your best vanguard healer. They are highly durable and offer a one cleanse ability that hits poison, magic, and disease. Priests are more versatile and provide barriers, but Paladins can hit divine favor (hope it doesn’t get dispelled), and land a big flash of light, or in rare occasions, a holy light. Most good teams won’t let you sit and spam holy light. But that’s where the elite shine. They position properly, BoP mages, and keep their enemies at distance. If you’re dispelling a Warrior, most people are going to have issues just getting through that and getting to you. Paladins are hardly as feeble as some suggest here.
And then you get to the holy God status of full T3, where your cleanses are also healing for 400+ coupled with the libram so it costs a paltry 50-60 mana. This is rare of course ;].
Ret, I love, simply because I can wander around EPL and walk up to scrubs, and promptly 1 shot. It’s one of the few classes outside of a Warlock popping ToEP and soul firing, or a Shaman doing the same with CL/NSCL/ES/LB combos that dispatch people as soon as you engage them.
It is a truly remarkably awful class that somehow always finds itself in groups, dungeons, PvP, at the top of leaderboards in BGs, and at the foot of a joke. I wouldn’t have them any other way.