At long last, Blizzard has set out what they expect the paladin to be. Ghostcrawler posted on the Beta forums:
I actually think you know what direction the class is moving towards, because you know your class. But I'll try and pontificate here for a moment if that's helpful.
Protection -- We want more tanks in the game. Main tanks. We think it's fun to have a diversity of players and see how different spells, abilities and class mechanics get used to solve problems. A Protadin with the right skill and gear should be able to tank any fight in the game. Previously, we tried to push Prot into the offtank and AE tank roles. While your abilities are still really well suited for AE in particular, overall our philosophy has changed and we want you to be able to do anything the other tanks do. Note that this means other tanks will get better at AE tanking though. Prot represents a special challenge when not tanking because you can both heal and do dps and some players want to do either. Or both. One final comment, that you have already seen, is we want you to gear like a warrior: collect Strengh and Stam and use tanking weapons instead of caster weapons.
Retribution -- You're a melee dps class, and one of only a handful of classes that can fill the "mana battery" role. With the changes to the way raid buffs work, we are blurring the lines a lot more between "pure" dps classes and hybrids that have the potential to respec if their dps doesn't work out. But we don't penalize classes for having awesome buffs the way we used to. Also remember that one of Ret's big limitations before was just getting in the group with the good melee buffs. That problem is solved. If you're good and know your stuff cold, you should be able to be up there with the rogues and hunters. Maybe not every fight, but not 500 dps below them either.
Holy -- You're still the best high-throughput, single target healer in the game. I suspect you're still going to get called on to heal the tank a lot. Holy was in a really good place in BC, so much so that other healers (probably priests more than anyone else) began to get overshadowed. To shift things back a little, as well to just challenge the player base, we introduced a lot more fights with AE damage and movement. Unfortunately, those mechanics hit Holy. Hard. At the same time, CoH and CH seemed to be able to handle any encounter. Beacon of Light isn't a panacea to solve all of those problems, but it is designed to help. It still needs a little work, but I think the basic spell design is sound.
One thing that has been mentioned is that the three paladin trees feel pretty separated from each other. We've gotten better in some other classes of making it a valid choice to go deeper into a second tree, and not just to get a single, incredible talent, but because there is some legitimate synergy there. It's going to be harder to get that feeling for the paladin than it is for the mage, but it is something we want to mess with some more after Lich King.
Obviously beyond the individual trees, we completely redid the whole seal and judgment system. We think it works pretty well, but we're just going to have to play with it some more to find the rough spots.
Well, that's the plan. Now we'll see how well Blizzard executes it.