Disease-less Blood is as good as gone, as expected. The basic strikes have had their up front damage nerfed and been given scaling damage on diseases, meaning it is now useful to mandatory for Blood Death Knights to keep Frost Fever and Blood Plague up again.
Of course, this means, for the moment, that the incredibly tight blood disease rotation is back, where you have to time your obliterates just right to prevent diseases from being eaten too soon. Death Knights are currently still working out the new dominant specs and rotations. Some Death Knights are trying to use Death Strike in place of Obliterate with varying degrees of success. Others are using Obliterate, often while doing without Annihilation in order to grab a Perma-Ghoul and extra Death Coil damage in the Unholy Tree. One thing that does help in that vein is the new longer base cooldown on the diseases, which should give a bit more leeway in spending runes and runic power before hitting the "clear diseases and do a lot of damage" button.
Blood is probably still a shaky tree for DPS compared to other options though, and if Blizzard still means to make Blood as powerful as Unholy and Frost DPS, they may need to do a bit of tweaking
One thing that Blizzard should probably do to properly "buff" Blood DPS is to take another look at the first few tiers of Frost. Moving Glacial Rot out of the first tier in favor of the incredibly useful Runic Power Mastery was a good first step, but something needs to happen with all the frost damage only stuff still left in the first two tiers. Both Blood and Unholy use Frost damage only sparingly, so having all those frost-damage only buffs in the first few tiers still feels a bit lackluster, especially when any tree can pick up a lot of useful things in the first few tiers of Blood and Unholy.
In particular, Black Ice needs some non-frost damage utility so that Blood Death Knights can feel less like they're wasting points if they want to pick up Annihilation. I'd suggest adding a +X% extra damage per disease on Blood and Heart Strike to the talent. This makes Frost a more rewarding secondary tree for both Blood and Unholy Knights. Blood Knights will get more physical damage to take advantage of Blood Gorged, and Unholy Knights will get more scaling on single targets due to their third disease.
If you can do that, or give Blood enough Death Strike buffing talents and glyphs that it becomes a valid DPS replacement for Obliterate, Blood should be in a good place, with solid DPS options at the baseline and valid secondary talent options in both the Unholy and Frost trees.
Unholy has not only remain relatively unscathed, but overall buffed rather significantly by the latest round of changes, with tons more scaling and a rebuffing of Gargoyle for deep Unholy DPSers. I'm still expecting Scourge Strike to get unbuffed to some extent, either by being made more resistable or by the new Outbreak bonus being slapped down.
One thing worth noting on Unholy is that preliminary research suggests that the new Glyph of Unholy Blight, which increases the duration of the ability by 10 seconds, may actually save us less runic power over time than the new Glyph of Death Coil, which reduces the cost of the ability by 8 runic power. This is something that may suggest that the Glyph of Unholy Blight needs a bit of buffing, since the other 2 major glyph slots for Unholy DPS will almost always be taken by the Glyph of Scourge Strike and the Glyph of the Ghoul. The UB Glyph, much like the Horn of Winter glyph, will pretty much be regulated to "I'm lazy" status.
There is also some concern that Ghoul Frenzy, the new haste and healing talent for Ghouls, just isn't useful as an ability at the moment. Much like the old Corpse Explosion, its main problem is that it requires one Unholy Rune to use, messing up Unholy DPS rotations by leaving an extra frost rune hanging out and doing nothing. Much like Corpse Explosion, it seems like Ghoul Frenzy should probably either be on Runic Power, or be made Frost/Unholy with some buffing to make it worthwhile to use over another Scourge Strike.
Deep Frost is still trying to find a place as well in the next order after the massive Howling Blast nerf, although right now it seems that Using Obliterate and Icy Touch to generate the runic power to spam Frost Strike is the way to go, and that DPS is still more than respectable that way. The complete eschewing of Blood Plague is still a hallmark of the Frost tree, which is honestly understandable given the fact that Black Ice and Glacier Rot continue to buff frost damage only.
Blizzard has already shut down disease-less Blood, but it's a bit more iffy whether they'll shut down one-disease Frost. If they do, they'll probably want to give Frost a few shadow-damage buffs to their talents to make up for it.
I'm estimating at least a good solid month left on the 3.1 PTR, if not more, so we can probably rest assured that more changes are coming. Still, Ghostcrawler has made it clear that they want more feedback on what is available, so the best I can say for any Death Knight, regardless of spec, that if you're concerned about your spec or your favored rotation, start testing and running numbers, then come to the official boards with numbers and logic. Numbers and logic that show where the weaknesses are, where the differences are, and logical reasons why they should be buffed. It's going to be a long, bumpy ride. We're on the first major live patch after the release of our class, so we should expect plenty of adjustments.