The rotation does not squeak
Most of Blizzard's changes lately have been numbers tuning as the beta begins to wind down. Some things have been hammered out; others are a little more glaring and will need to be fixed before the 5.0.4 patch. Hammer of the Righteous, for example, is scaling really well -- to the point that its AoE component is doing more damage to a single target than a Crusader Strike. And as such, in the recently announced build it was noted that HotR's AoE will be nerfed, a course which makes sense (since they seem loathe to buff Crusader Strike for design reasons).
But I'm digressing here. With Blizzard being occupied with their various knobs, we have a very clear idea now of what the rotation will look like in less than two months. In Cataclysm, the foundation of the rotation was a very frequent "heartbeat," a Crusader Strike that was used every other global cooldown. In Mists, the heartbeat is extended a tad, with Crusader Strike now having a 4.5-second cooldown, thus giving you two GCDs between each beat.
Right now, the rotation feels a little bit like CS, blank, CS, blank, CS, and then hammer Shield of the Righteous over and over until the damn ... thing ... actually ... hits. In Mists, Shield of the Righteous is off the global cooldown, so you won't be obsessively hammering it while ignoring all your other abilities and subsequently watching your threat evaporate until the fates and hit rating favor you. You can now just slip it between attacks, like a Heroic Strike. Because Shield of the Righteous doesn't hit nearly as hard in Mists as it does in Cataclysm and is much more survivability-focused, this change makes perfect sense.
The fillers for our rotation will primarily be Judgment, Avenger's Shield and Grand Crusader procs, Consecration, a level 90 talent attack, and Holy Wrath (though that's dead last on the list). In addition, we'll want to maintain Sacred Shield (if talented for that) and the Weakened Blows debuff using Hammer of the Righteous (even in single-target). In total there should only be two empty GCDs, give or take, every 30 seconds, so the rotation should feel very smooth.
Active Mitigation feels so good
Speaking of Shield of the Righteous (it was only a paragraph ago -- that was a valid segue!), the new design of active mitigation seems to have worked out. It's not terribly intrusive, it doesn't feel forced, and -- most importantly of all! -- it feels like it matters to use that button when actually tanking, which is the most important metric of all.
If you liked playing smart with Holy Shield and taking an active role in survivability beyond cooldowns, you're going to love how active mitigation is set up for us. Shield of the Righteous is fairly mechanical -- you want Bastion of Glory to stack, so you don't want to sit on your holy power too much and you'll thus be using ShoR fairly often. There's definitely something to be gained in occasionally micromanaging, especially in the hardest content, but I can't see myself sitting on ShoR the same way I sat on Holy Shield in Cataclysm.
Word of Glory, however, is something you'll definitely want to sit on. With a potential 50% boost from Bastion of Glory, you'll want to be doubly judicious with how often you hit that button. Wait for as high a stack of Bastion as you can stomach, and wait for the most optimal time to dump a huge heal on yourself. The overheal bubble is gone, so you can't just pre-empt a big hit; you need to WoG reactively.
Honorable mention goes to Sacred Shield, one of the new talents, which while not really anywhere near active in action will still need to be actively maintained. It's a pretty key talent, so prepare yourself for keeping it up every 30 seconds.
Holy power is generated much faster
A 3-stack of holy power can take between 4.5 and 6 seconds to generate in Cataclysm. In Mists, even with Crusader Strike at a 4.5-second cooldown, you can easily a 3-stack in 4.5 seconds with just Crusader Strike and Judgment (which now gives holy power on hit) or even in 3 seconds if you get lucky with a Grand Crusader proc. In short, the generation is a lot burstier. On average we're looking at 1 holy power every 3.5 seconds, according to simulations.
Essentially, holy power will be stacking much faster than we may be accustomed to, which is fitting with the new active mitigation system and how dependent it is on our golden combo points. Add on top of that the contribution of any of the level 75 talents (especially Divine Purpose), and you may find yourself with more holy power than you know what to do with.
All in all, thanks to how free our resource will be flowing, compared to other tanks we'll be hitting our main active mitigation button much more often than the other classes.
Versus other tanks
There was much gnashing of teeth in some quarters about the quality of paladin tanks vis à vis the encounters of Dragon Soul and specifically a widespread fear (among the noisier) that we were inferior with regard to the content. (Warriors felt similarly, but in their usual fashion, much more loudly.)
Truthfully, we did have a weakness to the quantity of unblockable damage that was so prevalent, especially in the harder and heroic encounters in that raid, that other classes simply did not have. What block couldn't cover for us, Blood Shield and massive quantities of bear ass were more than able to defend against.
We have some new tricks up our sleeve in Mists that will hopefully mitigate some of this. For example, we can WoG more often (and more effectively), which can take the sting out of large unblockable hits. The Unbreakable Spirit talent will on average give us a 40-second cooldown on Divine Protection and could even get us to a 5-minute Lay on Hands. Those both could be a huge boon to our survivability in high-unblockable damage situations. Moreover, the Holy Avenger talent with its short cooldown offers a massive burst of survivability with the possibility of nigh-chaining ShoRs and WoGs for 15 seconds.
In the end, I think we're positioned very well for Mists. There will always be fights where one class is better than another, but on the whole, we're not going to be starting the expansion knee-capped or anything.
Addendum: Mechanics change for Judgment
According to Ghostcrawler, Judgment is going back to a ranged melee attack. This appears to be for PvP reasons, since a silence would lock us out of a spell-based Judgment. No word yet on this reversion will also apply to Avenger's Shield, which was similarly moved to being a spell with Judgment. It likely will remain as a spell, if Judgment was changed primarily for the benefit of PvP rets.
The Light and How to Swing It shows paladin tanks how to take on the dark times brought by Cataclysm. Try out our four tips for upping your combat table coverage, find out how to increase threat without sacrificing survivability, and learn how to manage the latest version of Holy Shield.