well i have found that a blood DK does not do as much dps as the other specs but the buffs it gives is really good like the 10% to strength and are very welcome in a raid
but to answer ur question is crit and AP are very good u want around 2k+ AP and bout 23% crit.
now the seperating str and agil is hard to do since agil give crit chance and str gives AP
i would say str for the AP (for every 1 str u get u get 2 AP) then i would go with agil (62.5 agil turns into 1% crit)(i would like to add that you want to Keep in mind everyone has a base crit of 5% from agility.) my 80 DK have about 4-6 hundred more str than agil
i am not sure if this helped very much i tried with what i could if you still need some help just reply again i am on forums alot and will reply as fast as possible
I don't know why somone up there said that blood spec isn't good dps. I have two good dk bloods in my guild and they rape the dps charts. The better of the two is doing 7k+ dps. Maybe the blood spec you tried wasn't correct. Personally i'm a blood tank DW and I don't have a problem missing that much. I do 2.8K dps in naxx25 as a MT. currently my hit is only 200 as well. Another thing is to stack Strength not attack power with gems and such. The reason for this is because when you get buffs I.E. kings %10 to stats.....that's going to bump strength which in turn gives you more ap. As for agi you don't need to gem for that...just crit because your gear gives you the agil you need......raw crit is better then agil. Hope this has helped.