Kaz (can I call you Kaz) has done a great post on the upcoming Wrath of the Lich King info. You can read it here.
Personally I'm very concerned over how Blizzard will handle the tank balance issue.
If you'll remember, Druids went on this crazy roller coaster ride in early Burning Crusade. They came out of 2.0 (the patch that started our migration to Burning Crusade) very strong (some might even argue they were overpowered), then got reduced (nerfed) and slowly brought up to about right.
Warriors were always pretty good but early in tBC they had some rough times, especially with all the multi-target tanking needed in 5 mans and early Heroics. The foil to their scaling was that they started off a little weak.
Paladins were something akin to a baby giraffe. They were the new tanks, and their legs were pretty wobbly at first. They were consistently behind Warriors and Druids in Hit Points (the most visible 'tank' stat), and they had a huge inertia of preconceived notions to dispel. Even the most Ardent Defenders of the Paladin tank saw clear weaknesses as the Raid game began. The thought of a Paladin tanking even something like Gruul or Hydross was fodder for April Fool's jokes (yes, I still remember that one) in early 2007.
Even now, at the end of Burning Crusade, with all 3 tanks nearly equal, in the most challenging encounters like Brutalus, Paladins have been found wanting.
Now, Blizzard adds another 10 levels, 10 more Talent points, new spells, and new talents. As an added bonus, we have a 4th entrant to this seesaw balancing act.
Paladins seem like such an oddball compared to all other tanks (including Death Knights). They are the only Tank/Heal hybrid, while the other 3 are all Tank/DPS hybrids. Druids and seemingly Death Knights switching between the two a little more fluidly than Warriors.
Paladins are the only tank to start will a full resource bar and slowly deplete it over time. Warriors and Druids are Rage based and Death Knights work on a strange combination of Rage and Rogue energy.
Paladins are the only tank to be mana based, and the only tank crippled by Mana Burns (thank you Kaz'Rogal), and Silences (Hello Maiden, Gruul, Bear Avatar).
The Paladin niche seems to be fairly narrow as well. Warriors are setup for physical mitigation. Easy to see a Boss like that. Death Knights for Magic Mitigation. They basically replace Warlock tanks and may eliminate the need for a Warrior or Paladin to ever need resistance gear again. Druids are your fluid tank for places like Lurker where you have a temporary add that needs to be tanked, then go DPS the boss.
Paladins are your AoE tank, and in every occurrence of this 'niche' in Burning Crusade it could be done with either a Holy Paladin or a combination of Warriors and Druids.
I'm really concerned Paladins are going to be 4th string tanks in Wrath, and that would be really sad. It took Blizzard over a year to fix Paladin tanks (we weren't really up to nuff til about 2.3), I'm not holding my breath they get everything right from the get go this time around.
For me personally, the Death Knight doesn't hold much appeal. Much like the Warlock, the Death Knight is just too dark for my taste. I don't want to play a class with abilities with names like Death Coil, and Death and Decay. But over the course of Burning Crusade, I've come to enjoy tanking. It's fun for me and I don't mind the drawbacks that come with it (slower solo experience, repair bills, etc). I'm just concerned over where my class will be when the dust settles from 3.0.