Right. Bare with me, I have NO experience with playing a ret paladin whatsoever (I've got a paladin at 40, but he's been holy, prot and protholy). Note that I'm using the tooltip amounts of damage, you'll probably want to double them if you want a more realistic amount, I'm not sure how the gear and spec scales this stuff.
Abilities
It looks like you put up Seal of Truth first. It lasts 30 minutes and applies a 600 damage (5 time) stacking holy DoT on the target. Unleashing the seal by judging causes it to do 900 damage, and this damage is increased by 10% for each stack of the DoT applied to your target. Aka with 5 stacks, judging will do 1350 damage. There is also still the Seal of Righteousness, which simply adds 230 holy damage to all your attacks - judging it simply deals 1300 damage.
Judgement has been remodified to leave a 20 second debuff on the target which gives people attacking it a chance to heal them for 1% of their maximum HP. AKA judgement of light.
Then there's Exorcism, which deals 4600 damage to any target - if the target is undead or demonic, you get a guaranteed crit.
Next is Crusader Strike, which deals 132% weapon damage and gives you a stack of the new Holy Power.
Divine Storm still is what it was, except that it now works off holy power - it consumes stacks of Holy Power to increase it's damage. There is also a new ability, Templar's Verdict, which is basically the single-target version of Divine Storm. It deals more damage depending on how many stacks of holy power you have. The two abilities also cost the same mana (1716). It doesn't heal, though.
There's also the new Word of Glory, which is an instant heal (that goes on any friendly target, including yourself) that heals the target for 1500 per stack of holy power you have. This one doesn't cost any mana.
Inquisition is a self-buff, like feral druids have, that increased your holy damage done by 30%. It lasts for 10 seconds per stack of holy power.
Last but not least, there's the lastest 31-pointer, Zealotry. It's on a 2 minute cooldown and causes your Crusader Strike to generate 3 stacks of holy power rather than 1 on a hit for 15 seconds.
At the moment, the maximum number of holy power is three stacks. Also at the moment, they last for up to 30 seconds, regardless of whether you're in or out of combat. You refresh the duration when applying a new stack.
Talents that impact your rotation
-Eternal Glory is a 2-point talent that gives your Word of Glory a 40% chance not to consume holy power. Aka, if you're lucky, you get an additional heal or empowered swing.
-Communion adds the Replenishment effect to your Judgement, basically turning it into Judgement of Light and Mana at the same time.
-The Art of War gives your melee attacks a 60% chance to make your next Exorcism instant cast (it's 1.5 normally), though this won't work when Exorcism is on its 6 second cooldown.
-Rebuke is a new talent that is pretty much completely similar to a rogue's Kick. It costs 10 mana, interrupts the spell currently cast and locks the school for 4 seconds, and has a 10 second cooldown. No, the 10 mana isn't a typo.
-Sanctity of Battle makes haste lower the cooldown on your Crusader's Strike.
-Seal of Command has been turned into Seals of Command, and it causes your Seal of Rightenousness to hit 2 additional targets.
-Divine Purpose gives pretty much all previously named abilities a 40% chance to generate holy power.
-Sanctified Wrath allows you to use Hammer of Wrath whenever you're using Avenging Wrath. y so wrathful?
But what does it all mean, Holmes?
Well, from what I can understand, it works like this;
Crusader Strike is your main ability. You use it to gather up holy power to in the first place keep Inquisition running. As long as it's running, you use holy power on Templar's Verdict for awesome ST damage. At the same time, you need to throw in constant judgements there to keep yourself from running OOM (and do more damage). When you get an Art of War proc, you throw an instant Exorcism. During cooldown time, you pop Avenging Wrath and start throwing Hammer of Wrath in there, and pop Zealotry to allow for more Templar's Verdicts.
Or to put it quite simply, as my retadin pall said; you just pop whatever is off cooldown, and when you have 3 holy power and Inquisition is up, you use Templar's Verdict.
For AoE, it seems you use Seal of Righteousness and use Divine Storm instead of Templar's Verdict.
If you need healing (and trust me, this won't be just PvP situations with what Cata looks like at the moment), you can throw a Word of Glory around, and it'll hopefully only cost you a GCD.
Without even actually playing the class, I do notice there seems to be a great emphasis on survival and this ties in completely with my experiences of playing a rogue. Go check the rogue forums for my thoughts on that - I've found that survivability REALLY matters in Cata, and won't be surprised if cookie cutters pick up one or two survivability talents over pure DPS talents.
That said, I hope this helps. If you have any more questions Maz, let me know. I don't have a lot of hugely in-depth information (I've no clue how the class 'feels', I just wrote this up from reading tooltips and bashing a target dummy), but I've got a pall in the beta who plays retadin.