For as far as I've noticed, Unholy is still the way to go, even though (despite the big blood nerfs that ruined PvP) you see more blood DK's than before. That is to say, I've met about two since the last patch - 0 before the last patch. DK's seem a lot less represented in arenas anyway. One of the two DK's in question is apperantly around 2200 rating as blood (in 2v2), though I can't recall his name anymore. In my battlegroup's ladder, there's a grand total of 2 blood DK's in the top 50 2v2 teams (out of a total of about 6 DK's, iirc), but all of them have a very specific playstyle - one of them has a DPS-talents only blood spec which I'm guessing he uses while wearing Pve gear, and the other doesn't have *any* snares which makes me guess he's got a partner doing snares and CC's for him.
As for a conclusion on my original topic (now that you've necro'd anyway); I've been playing around with Blood PvP a lot more on my DK, and I've noticed that it should work decently in arenas (I reckon 2K is reachable easily enough). I managed to get myself up to a 1K rating with a paladin healer without any troubles and in mediocre gear. The way you're supposed to play it is kind of peculiar, though. I'll list the pros, cons and facts about it below. Keep in mind a lot of this is guesswork based on the 1800's experience on my rogue, though.
> Cookie cutter specs for the playstyle would be 44/0/27 or 54/0/17 (In the latter one, Sudden Doom and Spell Deflection might be interchangable, still playing with that. The glyph of Vampiric Blood is interchangeable for anything you like). Difference really is permapet and soft-slow on Plague Strike for more DPS/burst. Survivability is equal as +10% healing is more or less countered by needing to summon the ghoul before being able to Death Pact. The first spec allows you to open up with Plague Strike while the second requires that you do a Heart Strike on your target before putting your diseases up. Other specs may work but these are all-round probably your best bet.
> You win 95% of your arena matches by outlasting the enemy team.
> A match against any DPS/healer comp lasts at least 10 minutes.
> Counter-comp would be anything with a priest or frost mage, frost mage/disc priest being the worst possible combination you can face.
> You partly counter the warrior's ability to kill your paladin's bubble by being pretty much unkillable by warriors yourself.
> The Orgrimmar arena is probably the best arena for your team to fight in unless you're facing a team with a priest or frost mage - then it's the worst.
- Frost mages are the bane of your existence. Even more so than when being Unholy.
- The gear requirements are very, very specific. You need exactly 5% hit and 25%+ armor penetration to have any chance of success. To balance that out though, you do not need any spell penetration.
- This probably only works in a DK/Paladin comp, playing with any other healer means trouble.
+ You will rape double DPS teams. I can't imagine any comp more capable of taking them on.
+ Because of your obscene amounts of self-healing and the fact that your partner is a paladin, you literaly slow the game down to a snail's pace. If you're new to PvP or have problems with PvP going too fast for you, this is probably the easiest comp for you to work with (excluding pure healer/tank comps, but they are rarely succesfull, I reckon).
+ Aside from frost mages, you should be able to beat pretty much any equally geared class in 1on1. Additionally and partly because of this, blood DK's make for great defenders in AB and IoC.
+ IT'S BLOOD!
All in all I feel blood DK/healadin (holy or prot, doesn't matter) is probably the easiest comp to get into 2v2s with and while you don't have a lot of burst, your survivability generally allows you to control the game which has a lot of pros. It's not going to get you up with the pros at 2300+ but if you really want to, 2000 rating should be reachable which makes me believe it's perfect for casual arenaing. It's also a great spec if you're a solo PvP'er and you will generally be able to easily escape from the few classes you're unable to beat (read: frost mages).
Edit: Forgot a line.
Edited, Nov 20th 2009 3:38am by Mozared