The talk then shifts to dual-wield, in which he basically describes the new Threat of Thassarian talent, although I get the impression this Q&A was done before the patch 3.2 PTR notes were finalized and released, because he doesn't quite give specifics. The general goal, like they've said before, is that DW is an option, but not dominant. Both DW and 2H DKs should be viable.
Back to tanking, GC says (and I'm not sure if this is a typo or not) that they "wanted to make cooldowns the unique part of DK tanking." The unique part? Really? Anyway, obviously DK cooldowns are a bit overpowered for raid tanking, so they are being toned down a bit. Death Knights should still be able to tank any encounter (as should the other three tank classes, I assume).
This was also mentioned in the Mage Q&A, but they don't like that some stats are valued much more by some specs than others (ArPen). They don't want to make many different types of DPS plate; instead, they'll just try to make sure all specs benefit from all DPS stats.
A straight answer to the question of saving runeforges as part of your main/alternate spec: no. They're already convenient enough.
The discussion now turns to PvP. Players are concerned that there is sometimes a delay in Mind Freeze, which causes the interrupt to show in the combat log, but not actually interrupt. Unfortunately, the devs have never been able to replicate Mind Freeze acting differently than other interrupts, but they're still looking into it.
Other players may be concerned about DK self-healing in PvP, but Blizz is unlikely to do anything about it, as they see it as a core class mechanic. Chains of Ice, interrupts, or magic damage are a more likely target for nerfs if PvP nerfs are necessary.
Mortal Strike for DKs? No. DKs don't need PvP buffs, and if every Arena team ends up needing Mortal Strike, they'll just make it an aura that you get upon entering arenas.
Chains of Ice on diminishing returns? If necessary, but it's not currently planned.
Finally: are ghoul voices returning? Yes. They were removed because they had been using the vendor voices, which had some odd consequences. They will come back eventually.
Patch 3.2 will bring about a new 5, 10, and 25 man instance to WoW, and usher in a new 40-man battleground called the Isle of Conquest. WoW.com will have you covered every step of the way, from extensive PTR coverage through the official live release. Check out WoW.com's Guide to Patch 3.2 for all the latest!