Firstly I have relatively little experience with Wrath Tanking as a Paladin, I've done heroic tanking on my paladin which basically involved facerolling on 5 sets of keys and face rolling, yes paladin tanking is very hard ... :/.
However I haven't really raid tanked at all in wrath on a paladin, I've tanked some 10 man stuff on my warrior (Naxx and Ulduar) but nothing that major.
Lets get a few provisos I have about tanking out of the way. There are 2 ways I see a difficulty of class scaling, there are "Difficulty for the new player" and "Difficulty for the knowledgable player".
I generally consider the healer to be the hardest class to play, under the lk scope, especially Holy Paladins and to a lesser extent Resto Shamans because you don't blanket so much and you actually make individual choices on who to heal, you don't just shove out a rotation like the druid/priest or dpsers/tanks.
Then if you are a new player i consider tank to be the next hardest, since you are asked to lead a dungeon, often the tank dictates the pace of the run and is looked to for knowing tactics and stuff, especially at 5 man content this is the next difficult job.
At a raiding level however I consider the tank to be the easiest Job, and there are a few reasons why:
1) Gearing is pretty easy, you just go for the stuff with more stamina/armor on it in LK, thats pretty much all you gear for, you probably want to hit the hit cap and expertise soft cap for threat, but otherwise you are pretty much purely itemising for stamina
2) *Most* hard parts about a fight are avoided or mitigated by being a tank, ghosts on deathwhisper, Slimes on Putricide, Pact on Lanathel etc. Even if you fuck up on basic mechanics usually you have enough hp to survive.
3) Nobody Looks at a tanks rotation or threat, noone cares if it isn't 100% optimal, as long as people don't have issues with it, it's no problem: that means there is much more slack in a rotation of a tank than a dps.
Now Paladin specific in Lich King we have the fact that Ardent Defender exists, the only active dr cooldowns you have in LK is when to use Divine Protection and Divine Guardian, Discounting Glyph of Salvation, so mostly you can fully concentrate on moving, unlike say a dpser who has to pop his cooldowns on time you just have to do it at a specific point in the fight, say when you just taunt or are taking soul reaper.
These points all lead to me believing that tanking is the easiest part of a raid team in lich king, and that your tank can be significantly worse than the rest of your raid and you probably wouldn't notice or care as long as they geared right.
Like Blizzard has quoted many times Tanks are really only judged on success rate, you are judged on whether you were able to get through the fight or not.
Now, moving on to the actual topic of this post we have a few things that I like about the Protection Spec Iterations.
1) A real choice between threat and Damage Reduction. This change alone shows me that Tanking is moving to a more difficult level, I know Blizzard has said they don't want dps to have to worry about a threat ceiling and for Tanks to not worry about people pulling aggro, However to be Honest what I would hope that means is that a perfect tank with perfect dps would mean that the Dps were at a constant 85% of the threat level of a tank.
Since Perfection does not exist, this should mean that a Tank that can perform within 80% of perfection would be able to hold back 99% of dpsers without them really having to worry about taking aggro.
What I like about this system of choosing between threat and damage reduction is that it rewards those good tanks more, the best tanks that will pull out optimum threat and move bosses well and taunt at the right times meaning they can dump their Holy Power on Holy Shield instead of Inquisition. A system that rewards good players is something I definitly like.
2) The diversity away from warriors: the removal of shield of the righteous is great, I personally hated how samey warriors and Paladins felt. The Diversion of cooldowns between the 2 aswell is nice.
3) Cooldowns: Just gonna talk about cooldowns, I personally LOVE how ardent defender is changing, god that cooldown was such a total mistake in Lich King in my opinion, taking choice away from tanks just made them so easy and not taxing, it was horrible to see raid groups having to switch to Paladin tanks on Lich King for that insurance factor of Ardent Defender.
I remember chatting with some guy from Irae Aod who were one of the first groups to do 10 man Lich king (at the time of the conversation nobody had done 25 man heroic lich king) and they were like "yeh we wiped so much with a warrior and dk tank, but then we switched out our fully decked 264/277 tank with a t9 245/251 geared Paladin tank and 3 shot the boss." Comments like that really hurt me inside, the fact that one cooldown can give so much leeway on mechanics and make a difference between suceeding and defeat on an encounter, simply because the choice is removed from the player is really sad.
I like the new version of Ardent Defender aswell, a mini dr cooldown with basically 15% extra health, obviously it isn't clear whether it works on multiple blows that would have killed you or not but I don't think it would be that overpowered even if it did, considering it is only 15% healed. Regardless this is a really new and innovative cooldown and I like it alot.
I also like how Divine Guardian is being made into a strictly raid cooldown and not a personal cooldown, it seemed like a waste to have to save D.G. for a single person cooldown. It also means that having a Prot Paladin on your team gives your other tank 2 extra cooldowns (Hand/Divine Guardian) which is nice synergy as a tank partner, although perhaps a bit too powerful.
4) I like how Consecration is changing to make Paladin tanks more like well TANKS, you stand your ground, you want to tank in that spot and be like juggernauts.. that's awesome and compelling, obviously the rotation can support moving and using consecrate more but its nice to sort of only use it once every 45 seconds ideally and not have all this incidental damage.
I don't like how hammer is still the main nuke of Protection per-say: I am hopeful this will get iterated out or made a choice, considering also that they want to make Holy Wrath part of the rotation aswell means that Paladins are going to be just as good at aoe tanking in cata as they are today, since all their abilities to tank have incidental aoe. I would prefer a system where you have to choose between hammer doing single or aoe. Perhaps you could say make it so that doing C.S-> Hammer made it do single Target and Holy Wrath-> Hammer made it do aoe damage, it would be quite innovative to make certain spells affect the functionality of 1 spell but I feel like it would diversify the protection paladin class more: and make Paladins less good at aoe tanking (provided of course numbers were tweaked).
Obviously these are just ideas I'm throwing out but ye i just like the idea of using different spells to affect the functionality of this 1 spell. Exorcism could make it a ranged casted attack (like the trial of the champion boss) all this stuff, would just make it awesome and very unique.
I haven't really got much else to say other than that, it's hard to judge because I don't really play protection paladin's especially in the beta and am mostly just going off the talent trees and spells you use.
Anyway hope this wasn't too noobish of a random post