Since no one has replied in a while, I would suggest manually using Empower Rune Weapon when every single rune is on CD or time it with Heroism. It will be more effective since you can use it only 2 times a fight maximum. I also added Outbreak, HoW and Raise dead in the priority. See below.
/castsequence reset=target Howling Blast,Plague Strike,null
/castsequence reset=0.3 0,0,0,0,0,0,0,Raise Dead
/castsequence reset=0.3 0,0,0,0,0,0,Horn of Winter
/castsequence reset=0.3 0,0,0,0,0,Outbreak
/castsequence reset=0.3 0,0,0,0,Howling Blast
/castsequence reset=0.3 0,0,0,Plague Leech
/castsequence reset=0.3 0,0,Frost Strike
/castsequence reset=0.3 0,Obliterate
/castsequence reset=5/target HowlingBlast,Plague Strike
/cast [combat] Pillar of Frost
/use [combat] 10
/use [combat] 13
/use [combat] 14
/startattack
I use n52 which does about 10 clicks a second and what I have noticed is that I end up doing HB way more than OB as for most part the macro will fire off HB as soon as a single death or frost rune is available. I did some testing and just for kicks I reversed the priority list and for some reason the macro does more OB then HB. Below is the macro that I use and I do about 80k dps on a single dummy. My iLvl is 502 in 5 man dungeons I am doing around 110k on single bosses with NO Heroism/NO AoD. I have 100% up time for Frost Fever and about 97% for Blood Plague. The above macro is what I used to use and now I have switched to the following which does more DPS. I just typed it up so make sure the spell names are correct.
/castsequence reset=target Howling Blast,Plague Strike,null
/castsequence reset=0.3 0,0,0,0,0,0,0,Obliterate
/castsequence reset=0.3 0,0,0,0,0,0,Frost Strike
/castsequence reset=0.3 0,0,0,0,0,Outbreak
/castsequence reset=0.3 0,0,0,0,Horn of Winter
/castsequence reset=0.3 0,0,0,Howling Blast
/castsequence reset=0.3 0,0,Raise Dead
/castsequence reset=0.3 0,Plague Leech
/castsequence reset=5/target HowlingBlast,Plague Strike
/cast [combat] Pillar of Frost
/use [combat] 10
/use [combat] 13
/use [combat] 14
/startattack