So after many hours of testing, this is my 2 hotbar set which works perfectly. The only thing slightly disturbing is the animation my character makes when he tries to cast Blood Tap and there are not enough charges. But still it all works smoothly. These are a work in progress and may be altered as I level.
Single target Hotbar 1 - for soloing and leveling.
/castsequence [mod]Outbreak;reset=target Icy Touch,Plague Strike,Blood Strike,null
/castsequence reset=target Scourge Strike,Festering Strike,Death Coil
/cast Blood Tap
/swapactionbar 1 2
/targetenemy [noexists][dead][noharm]
/startattack
Hotbar 2
/castsequence [mod:alt]Icy Touch,Plague Strike
/castsequence reset=0.3 1,Dark Transformation
/castsequence reset=0.3 Horn of Winter
/swapactionbar 1 2
AOE Hotbar 1 - this needs superdupermacro and is the only way to make it work so far. Also Scourge Strike is only there to use Unholy runes - unused runes = less death runes so it is a dps gain to use all runes to gain extra death runes.
/castsequence [mod]Icy Touch,Plague Strike;reset=target Outbreak,null
/castsequence reset=5 Pestilence,Festering Strike,Scourge Strike,Blood Boil,Death Coil,Festering Strike,Scourge Strike,Blood Boil,Death Coil,Festering Strike,Scourge Strike,Blood Boil,Death Coil,Pestilence,Festering Strike,Scourge Strike,Blood Boil,Death Coil,Festering Strike,Scourge Strike,Blood Boil,Death Coil,Festering Strike,Scourge Strike,Blood Boil,Death Coil
/cast Blood Tap
/swapactionbar 1 2
/targetenemy [noexists][dead][noharm]
/startattack [exists,harm,nodead]
Hotbar 2 - same as above
My DK is level 81 - single target dps 8,500 - aoe dps 12,000
Talents : Unholy Blight, Lichborne, Death’s Advance, Death Pact and Blood Tap.
Other macros for DK - rezzes a dead player if targeted or if moused over a frame rezzes that player instead
#showtooltip Raise Ally
/cast [@mouseover,help][@target]Raise Ally
Heal pet without losing your current target
/cast [mod:ctrl,@pet][]Death Coil
Death Grip and stop your pet leaping to nowhere.
#showtooltip Death Grip
/petautocastoff Leap
/cast Death Grip
/petautocaston Leap
Very important cooldown usage - situational and does not stack with Heroism or Time Warp etc. Use wisely.
/castsequence [@player] Unholy Frenzy
/cast Summon Gargoyle
Self heal (no loss of current target) - life saver.
/cast Lichborne
/cast [@player]Death Coil
Edit - Modified the single target and aoe castsequences. With the aoe one previously, if Outbreak was on CD it would still try to cast it because it was at the beginning of the /castsequence hence a lockup. Added Blood Strike to use the left over blood rune for single target soloing. This was modified for leveling/soloing where Outbreak is always on CD. In a raid/party situation the single target one would look like this for hotbar 1.
/castsequence [mod]Icy Touch,Plague Strike;reset=target Outbreak,null
/castsequence reset=target Scourge Strike,Festering Strike,Death Coil
/cast Blood Tap
/swapactionbar 1 2
/targetenemy [noexists][dead][noharm]
/startattack [exists,harm,nodead]