He mentions a number of problems that have cropped up with Death Knights since launch (or before in some cases) and some potential ideas on how they can be fixed in upcoming patches. No official change announcements, just thoughts and discussion. If you want to see the full list, head on over to the forum thread. I'm just going to touch on a few that I've experienced firsthand.
Ghostcrawler mentions that Death Knights tank well when their cooldowns are available, but take too much damage when they're not. The potential fix being lowering the effectiveness of things like Icebound Fortitude, but boosting their baseline mitigation. A simple fix, and a good one. This is probably the single biggest annoyance when working with a Death Knight tank. They quickly go from having higher mitigation than any other tank to taking massive spikes of damage that you can't do much about except spam your heals harder. It's less than ideal, to say the least. I'm really glad that this is a recognized issue and something will be done about it. Right now, they're really not in line with the other tanks.
The ability Rune Strike came up: "Rune Strike was intended to be a reactive tanking tool, not a rogue killer. We will probably chill its weapon damage and increase its threat." Yeah, this is a good move. I think this is one of those things everyone saw a mile away. Rune Strike is basically Overpower combined with Revenge and injected with steroids. That's pretty wild and not what I'd call balanced at the moment. Toning down its damage is a good move.
It looks like there will be a whole bunch of changes to the Ghoul for ease of use, which I'm happy to see. Unholy ghouls need better raid survival than they have right now (considering they've become kind of important), and non-Unholy ghouls are just clunky and frustrating.
Ghostcrawler also mentions splitting the Raise Dead spell in half, one to raise players and one to summon your own ghoul. While this is a change mostly aimed at the 'fun factor' of raising your buds as a ghoul while keeping your ability to keep your pet ghoul, I think it will just plain help the spell's functionality.
I can't count how many times my raid's Unholy Death Knight tried to resummon his ghoul after a death and ended up raising another member of our raid that had died. It didn't do anything useful, just wasted a cooldown since its priority is to raise a player before creating a new ghoul. The easy fix is to wait until everyone is rezzed to use the spell, but making two different spells is a much more convenient fix. And yeah, way more fun.
There are more sigils on the way, and their absence is something my guildmates love to complain about, so I definitely can't wait to see them. They're aware of how hard it is for Death Knights to get their hand on Defense gear, and while they don't want to make tanking 2Handers, it is an option. My personal hope is they don't do to Death Knights what Protection Paladins had to go through for awhile. There were really only a couple 'Paladin weapons' that had real tank stats alongside their spelldamage. Beyond that, you just stole whatever caster weapon had the most Stamina. Kind of a pain. I'd much rather see a more graceful fix, like converting weapon DPS into some sort of defensive stat or ability.
Overall, I think these are good changes. As awesome as the class is in certain aspects of the game, it's bogged down with quite a few problems of its own. I hope to see everything get into working order sometime soon.