A few thoughts...Lichborne has amazing healing potential and can easily top you off, but only if you have the RP for it.Purgatory can save you from sudden spikes. But that 3 second grace period only lasts 3 seconds or until you get a positive healthbar again, whichever comes first. Get healed fast or die.
Glyphed Outbreak: yes, it means you can't open with it, but you shouldn't be opening with it anyway - first priority is threat. A DnD + DS will net 30 RP, 1 melee hit (which is highly likely) will be the other 10 RP (from Scent of Blood) allowing you to easily spread diseases every pull. You'll also only need to do this once - Blood Boil refreshes diseases. I'm liking this glyph more and more.
Roiling Blood: this is by far the best talent in tier 1. Blood Boil is already part of your rotation, making it also spread diseases is just amazing.
Lichborne vs Purgatory: personal preference.
Death Pact, Death Siphon, or Conversion:
Death Pact is an amazing 50% life-saving heal when you need it. Combines very nicely with Purgatory and/or Vampiric Blood.Death Siphon, not quite as strong a heal as Death Strike. However, the 40 yard range is really nice, and it does decent damage. Only marginally useful in dungeons though.Conversion gives you a trickle of health. This is what a healer is for, and is only slightly more healing than the extra Death Strikes tier 5 would have turned that RP into. This is a PvP talent, for DPS specs.
Tier 5: Again, personal preference. The difference is style.
Blood Tap, you choose when to get your extra runes for that extra Death Strike.Runic Empowerment, this is what we had in Cata, gogo rune tetris.Runic Corruption, to me, gives by far the smoothest rotation.
Heartstrike: sadly, this ability is close to worthless now. Yes, it does do (marginally, at low vengeance levels) more damage single target than Blood Boil, but by the time you get 2 mobs Blood Boil is going to be doing basically the same damage. Add a 3rd mob and goodbye Heartstrike. I took Heartstrike off my bar and completely replaced it with Blood Boil. 98k dps on Sha of Anger says I haven't lost anything.
DnD -> DS -> BB (if needed for the RP) -> Outbreak -> BB
If I'm pulling quickly and DnD is not up, I'll have saved enough RP from the previous pull to use Outbreak + BB right off the bat.
DS > RS(at high RP levels, to avoid capping) > Crimson Scourge proc (DnD when possible, else BB) > RS > BB