My issue with the skill usage section is that it's too wall-of-texty and still misses several skills. Then there's the Runic Power section only talks about RE.
I'd much rather have something like this: (hint this priority is for rc/bt and doesn't work well with re)
1) Use Death Strike when needed (further explanation later)
2) Keep up diseases (Apply with Outbreak, use Blood Boil if it is about to run out)
3) Keep 1 pair of FU runes on cd (unused runes equal less Death Strikes - only delay if you need 2 Death Strikes in a row)
4) Use Runic Power: (to proc RC/BT) Rune Strike
5) Use Blood Runes: (for dps/runic power) Heart Strike (up to 3 targets and >35% target hp), Soul Reaper (target hp <35% by the time it runs out) , or Blood Boil (3/4 or more targets)
6) Use Crimson Scourge procs for Runic Power (Death and Decay is more dps than Blood Boil but harder to use and doesn't refresh diseases)
7) Horn of Winter for RP if nothing else is ready.
---------- Post added 2012-11-14 at 02:36 AM ----------
Then I'd like to see some mention of the synergy between Bone Shield and Blood Shield either in the advanced section or in the Bone Shield description:
On certain bosses (like Gara'jal) with 2 tanks rotating every 30sec+ this can make a significant difference. Since Bone Shield only loses stacks when you take damage spamming DS (and thus refreshing your Blood Shield) may allow you to get a close to 100% uptime on both Bone Shield (since Blood Shield prevents you from losing stacks) and Blood Shield (since Bone Shield reduces damage taken by 20%).
---------- Post added 2012-11-14 at 04:17 AM ----------
I also think the talent section could use a complete rework. As of right now it's way too confusing since the guide tries to explain all skills at the same time and it's hard to find out what the op thinks about which talents fit a certain situation:
Imo it'd be clearer if you first write an explanation for each skill and then add a conclusion that describes when each of those choices may come in handy:
Tier 1:
Plague Leech: In theory this talent allows you to gain 1 Death Rune every 25 sec at the cost of having to reapply your diseases. In practice though reapplying diseases without Outbreak ready costs 2 Runes and a single Death Rune is worthless unless you are specced into Death Sipphon (or Have RE/BT to get a pair). It's also on the gcd which makes it kind of slow.
Roiling Blood: Allows you to spread diseases with a spell you already use in multi target situations. As a bonus it also doesn't suffer from the melee requirements regular pestilence has.
Unholy Blight: In general a blood dk doesn't really need this talent since we can easily maintain diseases with Outbreak, Blood Boil and Roiling Blood is usually all you need to spread them. In some situations, where your diseased targets are unattackable (Gara'Jal) or die regularly (5 mans/challenges) or applying diseases via Outbreak/Pest is too slow (Shek'zeer) this may come in handy.
T1 Conclusion: PL for pure single target fights if you also have Death Siphon (T4) and/or BT/RE (T5). Roiling Blood for pretty much everything that is not single target. Unholy Blight if you need another way to apply diseases.
Tier 2:
Anti Magic Zone: For single, high damage, raid wide, spell damage aoes (Elegon add explosion,...) this talent ignores the damage cap and can absorb millions of damage. Outside of those situation the absorption is fairly insignificant though.
Purgatory: A passive live saver that prevents your death... at least temporarily - what else would you need? It still won't save you from massive overkills and there's also the small chance you die from a dot tick right after you get healed just enough to leave the Purgatory state.
Lichborne The most interesting part about this is being able to heal yourself with Death Coils. This, however, only works well if you've already pooled a large amount of Runic Power and usually doesn't work well as a reactive cooldown.
T2 Conclusion: Purgatory for general tanking, Lichborne if you can fit in the extra cooldown, AMZ for situations as described above.
Tier 3:
Death's Advance: Movement speed is almost always useful and this one (unlike other MS increases) stacks with the boots enchant.
Asphyxiate: Stuff in raids tends to be immune to that and even if they are not this doesn't sound too appealing.
Chilblains: Reliable and easy to apply slow (just spread diseases) - as a bonus you also get the ability to root targets with Chains of Ice.
T3 Conclusion: In general you'll want Death's Advance, but on bosses like feng with adds that need to be slowed Chillblains may come in handy.
Tier 4:
Death's Pact: Massive self heal that requires your ghoul to be summoned (not much of a problem since both are on a 2 min cd)
Conversion Weak periodic heal that requires a lot of RP to maintain and disables the RP gain from Scent of Blood.
Death Siphon: In general this is a small dps gain over DS coupled with a large survivability loss,.... if however you have a massive buff to healing taken and or damage dealt Death Siphon can deal/heal massive amounts of damage.
T4 Conclusion: In general Death's Pact works best. However some bosses like Elegon, Mel'Jarak and Amber Shaper take massively increased amounts of damage and make Death Siphon a reasonable choice. I can't see Conversion working unless some mechanic grants you greatly increased rune and/or runic power generation so it's pretty much a no no atm.
Tier 5:
Runic Corruption: Since this talent increases rune regeneration speed all you need for it to be effective is to have runes being on cooldown while it's buff is active.
On average this talent will cause each Rune Strike to regen 45% x 0.3 x 2(3) x 1.2 = 0.486 runes (0.324 of those being FU runes)
Runic Empowerment: This talent used to work well in cata since Blood Tap allowed us to have a 5th Death Rune giving each RE proc a decent chance to grant another Death Strike. Since MoP we no longer have the old Blood Tap and the only way to get another Death Rune is through Plague Leech. It works well with Death Siphon since that only requires 1 Death Rune - for regular use with Death Strike it is not recommended since it loses most of it's effectiveness if you sit on runes.
Optimally this talent will cause each Rune Strike to regen 0.45 death runes - in practice however this is a lot lower
Blood Tap: With this choice you trade quantity for quality - meaning you'll have less runes gained overall, but get some control over when you want to have them.
This talent grants 0.4 Runes per Rune Strike
T5 Conclusion: Runic Corruption is the default choice since it requires the least amount of attention to use while still providing a decent and steady increase to rune regen. Blood Tap can be good if you need the extra control (and have the skill to use it well). Runic Empowerment is not recommended unless you don't care about using DS efficiently or are running with a Death Siphon spec.
Tier 6:
Remorseless Winter: On fights with stunnable adds this can be useful (Shek'zeer). Usually mobs tend to be immune against stuns though
Gorefiend's Grasp: Great for pulling casters or otherwise seperated adds in to aoe them. (Feng's shadow phase and 5 mans/challenges)
Desecrated Ground: Grants immunity to some cc effects, useful if there's actually an ability this talent is able to counter.
T6 Conclusion: Not much to say here since they are all very situational.