I realized the previous post ended up being really long. I'll try to summarize it. With how I write, I'll end up adding more thought, though still in fewer words.
Ret paladins sacrifice personal damage for abilities which increase party and raid damage. I like this idea. My worry is that it does not actually hold up. Other classes have buffs and debuffs which multiply damage. Paladins do not hold a monopoly on this, so if they are weaker in personal damage, they should be stronger in utility.
Looking at enhancement shamans it is easy to see a huge party damage increase. Unleashed rage is around 5% more damage for melee classes, much closer to 10% for druids. WF totem is a huge damage increase, especially for two-handed specs like arms which themselves give 4% more physical damage. JoW, possibly the strongest judgement, can be maintained by a tanking paladin.
What ret lacks in personal damage, it should make up for with multipliers to raid and party damage. Diversity in raids should be encouraged and create stronger raids. four rogues and a hybrid should be stronger than five rogues. Switching another and another should be even better and better.
But maybe all my thinking is for nothing. Others with more knowledge and motivation can run the numbers and show what utility ret brings, how that increases damage,and therefore how much damage ret needs to be equal to another DPS. Besides, ret paladins are in raids and are wanted. Can a spec really be underpowered if people want to play it and play with it? Isn't this a game, shouldn't it be driven by what we want to do rather than a set of equations?