Over time, we found we had intent to make mention of something such as the state of healing in Wrath of the Lich Ling, Death Knight and Hunter changes for you who were badly deeded. Now it is the time to talk about them in depth. See below:
In Wrath of the Lich King, to make tanking more is easier but challenging. We have tanked and healed a lot on various classes and we feel pretty confident saying that tanking can be much harder than healing on some fights. Challenging the DPS classes is harder, but you often see it in the form of berserk timers- if the DPS can't maximize their output, then the raid is going to wipe at no fault of the healers. Repositioning fights often tax the DPS characters, though to be fair, they often tax the healers too.
   We are pretty happy with the current state of tanking, modulo polishing up a few bits here and there. Healing is something we have committed to taking a good hard look at now, so threads like this are helpful. Unlike tanking, it is a harder problem to solve, in part because some healers like the way healing works now just fine thank you, and risk walking away from it if we make very dramatic changes. The kinds of dramatic changes that get suggested a lot are things like causing damage to heal, having to heal through the main game window and not the health bars, having combo points and that sort of thing. "That sounds awesome!"
Others say having better UI and more diverse spells to rely on, not having to time things so tightly or something to do besides healing will make their game more fun.
We do think the game can handle more diversity in healing mechanics than it can in tanking mechanics. That is to say, it is good for healers to have niches more than the tanks. This is largely because raids require more healers than tanks.
   Then let us get down to Death Knight. Death knights are a cooldown-based class. They can't count on abilities being there and ready to the same extent other classes are. In return though, they have an unlimited resource that neither goes away over time nor is dependent on doing damage or taking damage. While a DK may struggle a little more when things get out of control they are also fantastic in other situations -- you can actually battle rez a fallen DK tank and have them get back in the fray because they don't need to build up rage or mana first.
The rune system definitely has some strengths and weaknesses and that is by design so that the DK actually feels like a different class using different mechanics. Cooldowns won't appeal to everyone, just as drinking to restore mana doesn't appeal to everyone.
Now, that said, we do hope to be able to post some more definitive changes to Death Knights soon and one of the things that comes up a lot is removing the cooldown from Pestilence.
Lastly, it is Hunter in turn. That isn't to say that there weren't some good responses in that thread, or we don't understand the issues or aren't working on the problems. We have some Hunter PvE nerfs and PvP buffs we're working on and hope to be able to announce soon.
On the subject of Hunter changes, there are some disagreements. It is absurd to say that we haven't made any attempt to address PvP concerns. They may not be the changes you would have made in our shoes, but the Hunter class of LK looks dramatically different than the one of BC. It's fair to say that the changes aren't sufficient if you feel that way, but let's at least be precise; it's just silly to say no changes were made or that we ignored the issues.