Still, a lot of people will probably be disappointed if there's no new class-based toys to play with, so Blizzard may still make an attempt to add new abilities. So it may be worth it to assume they will. If so, what could we see for our new slot?
One possible way to provide new toys for the classes is to create new passives that modify existing abilities or provide interesting bonuses. In that vein, my personal pipe dream would be to have the tier 15 raid 2 piece set bonus become our new level 97 ability. When we attack, we get a chance to summon an undead pet to assist us. You could make them standard ghouls, or make them a random type of undead, similar those summoned by Glyph of Army of the Dead. If having all those ghouls in melee range is too much, you could also stick to having the ability summon ranged mobs, ghosts or banshees or even skeletal archers.
This type of ability has a few things going for it. First, it prevents button bloat by being a passive ability. Second, it fleshes out an aspect of the "look and feel" of death knights that has always felt a bit lacking on the PC side: Command of the forces of undeath. Certainly, unholy death knights get close with their ghoul lieutenant, but with the prohibitive 10 minute cooldown on Army of the Dead, you never really feel all the way there. This passive could do the trick and solve a few problems at once. Plus, let's face it, commanding an undead army at all times is pretty sweet.
Of course, demonology warlocks might get a little hurt if we basically get a cooler version of their Wild Imps spell, so if not that, what? In the theme of returning abilities, I would love to see a return of the old Wandering Plague, in which every disease tick has a chance to "explode" for extra AoE damage. Since it would be disease damage based, in theory it could shore up unholy's weaker AoE damage without, in theory overpowering frost death knights. To me, AoE damage and undead control are the two major areas I'd love to see death knights expand their grasp, so a ability that addresses one of those is still high on my wish list.
The Runic Runaround
Our rune regeneration tier was definitely one of the most talked about during the Mists beta. The most vocal faction (of which I was one, I will say in the interest of full disclosure) wanted it completely removed and replaced. Since rune regeneration was made such a key part of our class in Cataclysm, having your rune regeneration choices on a talent tier doesn't make them compelling. It makes it an obligation. Essentially, what it comes down to is that you choose either the option that will optimize your DPS, or, if you're more casual, the option that's the least hassle, which is usually considered to be Runic Corruption or Blood Tap macroed to your runic power dump.
As a choice, it's just plain not compelling. It was originally a change to our mechanics that no-one asked for, and while the choice of talents is better in that it allows death knights to choose to avoid the dreaded "rune tetris," it's still there and it's still a choice that's not compelling or exciting.
So for me, I'd like to see Runic Corruption made baseline, which keeps the rune regeneration mechanic intact if they insist on keeping it. Then, they can hopefully find some more compelling talent choices to swap into that tier. I'm thinking some defensive stuff like adding a damage shield to Icebound Fortitude or a knock back immunity skill, or maybe even a skill that gives you some passive defense or a chance at a defense proc based on how many diseases you have active on nearby mobs.
I admit, I've learned to love the level 90 talent tier for death knights, but part of me still prefers the major damage boosts that I got from getting my level 90 talent on my paladin and hunter. This also, I think explains the issue with the rune regeneration tier. A talent tier works best when it increases your power in a new and interesting way, whether it be giving you a new damage move, or giving a new and unique mechanic that allows for a feeling of power, such as our level 90 talents. Rune regeneration is neither of these. It's an obligatory choice for a much-maligned necessity of our class. Talents should be more exciting than that, so if I could change one tier of our talents, it would be that rune regeneration tier.
Learn the ropes of endgame play with WoW Insider's DK 101 guide. Make yourself invaluable to your raid group with Mind Freeze and other interrupts, gear up with pre-heroic DPS gear or pre-heroic tank gear, and plot your path to tier 11/valor point DPS gear.