One of the authors in the tanking community that I enjoy reading is Lore. Here
is a good recent post from him regarding some remaining polishing for Paladin tanks:
This is a collection of what I feel are the last few tweaks the Protection Paladin needs to be "finished." This is based largely on my experiences in Beta, both as a tank and as a DPS.
I'm only going to mention this briefly, as Blizzard has stated several times already that they're working on another mitigation pass. Prot Paladins are ever so slightly on the low end of the mitigation spectrum at the moment. We only have 6% built-in physical damage reduction from Improved Righteous Fury, compared to the Warrior's 10% from Defensive Stance and the Druid's 12% (15%?) from Protector of the Pack. If Block is meant to be how we are to make up that difference, our Block needs to be increased by a fair bit, as we barely break even with Warriors in overall damage reduction from blocking.
We're also falling behind a fair bit (along with Druids, I believe) on the spell mitigation front. We simply can't stand up to Death Knights and Warriors against caster mobs, especially where Spell Reflect is available. I like seeing Spell Reflect usable more frequently, and Death Knights have suffered through enough nerfs already, so it seems the best option here is to boost Prot Paladin (and possibly Feral Druid) spell mitigation a little. Personally, if we're to be the "block tank", I'd like to see some portion of our block value applied to spell damage somehow.
Wrath thus far is shaping up to be the final nail in Reckoning's coffin. With no real threat modifier on physical damage, internal cooldowns on Seal of Wisdom and Seal of Light, and Seal of Vengeance/Corruption becoming our primary tanking seal, extra melee swings really aren't that useful anymore. They're definitely not worth 5 talent points for a 10% chance on hit. Something needs to be done with Reckoning to make it worth consideration, or it will be dropped from the Prot Paladin build entirely. It doesn't have to be anything amazing; a good fix might be to just make the extra swings do Holy damage.
Righteous Defense is an awesome tool that works well until you have to work with another tank. The Paladin's lack of a single-target precision taunt requires a substantial amount of extra coordination out of Warrior, Druid, and Death Knight tanks working with a Protection Paladin. Worse, it's nearly impossible for a Protection Paladin to work properly with another Protection Paladin in multi-target situations like trash packs, or even boss encounters like Four Horsemen where tanks have to taunt bosses off of each other. One Paladin ends up with everything, while the other just whacks away trying to build enough threat to peel the mob they're trying to get back. The end result: Prot Paladins are annoying to work with. We need a single-target taunt of some sort, even if it's on a long cooldown or shares cooldowns with Righteous Defense.
Warriors don't have to rebuff Defensive Stance, Druids don't have to rebuff Bear Form, Death Knights don't have to rebuff Frost Presence, Paladins shouldn't have to rebuff Righteous Fury. The fact that it's dispellable occasionally causes problems as well (first few packs in Blood Furnace, final boss of Old Hillsbrad). I'd really like to see this made more along the lines of Shadowform or Hunter aspects, as an undispellable "Lasts until cancelled" buff. I'd even take just a duration increase at this point. I'm tired of losing aggro because my 30-minute buff wore off in the middle of a fight and I didn't notice.
The Paladin class has 3 unique buffs that stack with everything (Wisdom, Kings, Sanctuary). Two will likely be considered required for min/max progression (Wisdom and Kings), and the third (Sanctuary) is a second blessing from the Prot tree which will not likely be castable in many situations (as the Prot Pally will probably be the one with Kings as well). Holy Paladins sacrifice a lot to pick up Kings (at best, they lose 5% spell crit). Ret Paladins can pick up Kings fairly easily, but will probably want to buff Improved Might instead. This is problematic for raid composition.
My suggestion would be to make Blessing of Wisdom not stack with Mana Spring Totem (they're nearly identical in function), and to slightly rework both Blessing of Kings and Mark of the Wild to be identical -- Add the armor and possibly the resistance bonus to Kings (resistance bonus doesn't stack with auras anyway, so that might not be necessary), and make Mark of the Wild 2% stats baseline with a 10% bonus at full Imp MotW.
Direction When Not Tanking
The Protection Paladin seems to be somewhat torn at the moment as to what its role is supposed to be when you just don't need another tank. Warriors, Druids, and Death Knights are all being pointed towards DPS as the non-tanking utility, largely because it serves the new "Tanks as DPS" direction the game is taking quite well. Protection Paladins are being mostly pointed that way, with our two new offensive spells and all-around DPS increase, but we still have one talent deep in the tree that gives us a Spellpower bonus from Stamina as well as increased effect of critical heals. We're currently taking it for the little bit of threat increase it gives, but the healing bonus seems misguided. Having Prot Paladins off-healing simply doesn't fit well in the overall scheme of things. We need to be put firmly in an off-DPS role when not tanking.