Desecration: This talent has been reduced to 2 points for 25/50% snare and no longer increases damage done by the Death Knight. It has also been moved one tier earlier in the tree and its spell effect has been made more transparent. This is probably technically a nerf, since it removes a whole portion of the talent, but it works to separate PvP and PvE functionality as well. I imagine we'll see some attempts at PvP builds that make a point to grab this talent but leave Desolation (new talent, see below) alone, while tank PvE builds may or may not grab it for the threat and group gathering ability, and pure PvE DPS Death Knights will leave it alone.
Desolation: New talent. This talent is in the position formerly occupied by Desecration. It causes Blood Strikes to increase all damage the Death Knight deals by 1/2/3/4/5% for 12 seconds. This talent has a lot going on. While it no longer has the snare area of effect, it does apply the damage buff directly to the Death Knight, which means you'll have more freedom to use it on the run.
This also highlight's Blizzard's apparent attempts in this patch to emphasize Blood Strike as a viable DPS strike for Unholy instead of a death rune generator. Given this talent, the buff to Blood Strike, and the nerf to Scourge Strike, I wouldn't be surprised to see some Unholy Death Knights try dropping Reaping and simply trying out a rotation that sees Blood Strikes used in place of that extra death runed Scourge Strike.
Summon Gargoyle: The gargoyle now flies lower to the ground, making it susceptible to melee attacks. This ability now has a fixed duration of 30 seconds and a fixed cost of 60 Runic Power. While this change is similar to the Dancing Rune Weapon, it's arguably a bit of a nerf, since the Gargoyle can currently stay out for up to 40 seconds, and of course is out of reach of melee attacks. Of course, that Gargoyle takes quite a bit more Runic Power to maintain, Runic Power you can spend on Death Coils instead. This is a slight DPS nerf in theory, but the convenience may just make up for it.
Unholy Blight: This talent has been redesigned. It no longer deals damage to nearby targets. Instead, when you deal damage with Death Coil, the target will take periodic damage for 10 seconds equal to 30% of the damage done by Death Coil. This damage accumulates in the same way as Ignite and Deep Wounds. I have to admit, when I first saw this change, I was rather dismayed, but not even really for balance reasons. Unholy Blight is a very fun spell for me, flavor wise. Here I am, a big scary Death Knight, so potent that an aura of death and destruction surrounds me. But it was also powerful in certain situations. Unholy tanking becomes near trivial when you can just fire up Unholy Blight to pull in all the mobs around you. Likewise, in battles with many adds, Unholy DPSers do obscene DPS when Unholy Blight hits.
Interestingly enough, this may end up being an overall DPS buff. As it is, Unholy Blight on a single target is only very, very slightly better than Death Coil, and using Glyph of Dark Death and the new Unholy Blight, we may see some very nice single target DPS increases from this talent. It will also be interesting to see if the Glyph of Unholy Blight get a change. My gut feeling is that it will - an extra 30% damage from a glyph may be a bit much, even if it is spread out over an extra 10 seconds.
I'll still miss the flavor of that Unholy Blight area effect, but we'll still have Pestilence, Blood Boil, Wandering Plague, and so on. Overall, this will make Unholy tank threat a little bit harder and reduce our position on DPS meters on big groups of mobs, but the single target DPS increase may just make up for it.
Scourge Strike: Weapon damage bonus reduced to 40%, down from 45%. Damage increased by 10% per disease on the target, down from 11%. Given that we're getting some decent damage buffs elsewhere, it makes sense that they'd have to slightly adjust Scourge Strike to match. It's worth it to note that while Scourge Strike may sometimes seem to low damage, it does do shadow damage, which ignores armor, making it do more damage that you might first expect. I doubt the DPS nerf will be too seriously thanks to the Unholy Blight Buff and the Blood Strike buff.
One more thing bears mentioning in the Unholy category: the change that allows pets to share your expertise and hit rating, assuming it applies to Ghouls, could be huge. Permaghouls, to me, feel like the big flavor centerpiece of the Unholy tree now that Unholy Blight has been retooled into something less flashy, and the ability for them to gain some decent expertise and hit should give them a nice little DPS increase.
What to watch out for on the Patch 3.2 PTR
While I do maintain that we should have expected these tanking nerfs, and they do seem to target exactly where we were overpowered, you shouldn't take my word for it. Then again, we probably shouldn't demand they be reversed without giving them a fair shake either. My biggest concern with the nerfs is that they just may be too much when combined with some of the other class changes. Most notably, Paladins are getting some pretty sizable tanking buffs, and there's that removal of the armor buff coming to Inspiration and Ancestral Healing that I mentioned earlier. To top it all off, Block value is going through the roof as well. It's possible some of these changes may combine to make our tanking nerfs a bit more comparatively harsh than they need to be.
The good news is that we may not even see some of these nerfs make it to the PTR even now. My guess is that either the Frost Presence or the Toughness nerf will be reversed even before they see the PTR, though the Icebound Fortitude nerf is probably here to stay, if only to bring our cooldown potential in line with the other tanks.
What we can expect otherwise in the PTR is a lot of dual wielders feeling out exactly how frost 2-handing works out with the new talents, and where the best place to put talents is since the new skill suggests a focus on weapon damage whereas before Death Knight dual wielding was all about the extra magic damage.
We can also expect Unholy Death Knights feeling out their new rotations. The new Unholy Blight and the new Blood Strike, combined with the nerf to Scourge Strike, is going to lead to some soul searching on Glyph choices and rotations. Some may drop Reaping altogether, some may keep it and use one death rune for Ghoul Frenzy and the other for another Blood Strike regardless. Others may bring out the Glyph of Blood Strike and even use it to replace Glyph of Scourge Strike. It should be very interesting to see how Unholy combat shapes up in Patch 3.2, to say the least.
Beyond that, there's no denying that it does suck to be nerfed, and I myself will still miss the old Unholy Blight. However, if you believe any of the nerfs are too harsh, the best way to combat it is to get the on the PTR, do tests, get some numbers that prove your fears, and send them to the developers. For my part, I'll be watching the PTR with great interest, but while I'll miss the old Unholy Blight, I can't say any of the nerfs have me too concerned, overall. Hopefully we'll get a chance to see how this all plays out on the PTR soon.