Hey again Brut - been a while since I replied. Even though the guide has seen major improvements, lots of things are still off. As always, it's meant as constructive criticism, even if it's presented in a cynical tone. I will focus on PVE, seeing as I don't PVP much on my own Death Knight.
You write that Ebon Plague increases all disease damage by 30%. It only increases your personal disease damage, and does not boost diseases from other Death Knights or Shadow Priests. As such, your statement that the Unholy Death Knight brings something unique to the raid in form of Ebon Plaguebringer is also wrong, seeing as Warlocks, Balance Druids and Assassination Rogues also apply this debuff.
If you wish to advertise that Unholy brings something unique to the raid, you could mention Unholy Frenzy. It is a Power Infusion type buff for physical DPS, and can only be acquired by Unholy Death Knights. Seeing as Fury Warriors get immense PVE buffs in 4.1, they will most likely become among the highest DPS classes (perhaps beaten by Arcane Mages and MM Hunters), and with the high benefit they get from the frenzy buff, this might be something you'd want to mention.
Not something directly related to the guide, but your claims about your own DPS seem to be rather out of place. Doing 8200 DPS on a fight like Teron which in some cases can take as little as a minute with a full 70 raid, where you'll have either BL or Unholy Frenzy up all the time is not an accurate representation of what Unholy can deliver in terms of DPS. If you actually are doing 6500 sustained DPS, I would like to see how you manage this, seeing as it's well above what is theoretically possible in a sustained, uninterrupted DPS environment. Once more, burst DPS on a short fight does not accurately represent the specs damage output. It should also be noted that, while you claim to have best-in-slot gear, is it actually not true.
In the spec section, you write that you chose Resilient Infection as your filler point because it is the best option, but in the spec you linked, the leftover point is put into Desecration. I'm also wondering why you list RI as "the best option", seeing as, if my memory serves correctly, no mobs in TBC apart from the Bloodwarders before Kael'Thas dispel diseases. I would personally put the point in imp. DG, seeing as many pulls, particularly in Sunwell Plateau, have a high amount of casters which can prove to be a nuisance for your tanks. Being able to grip them more reliably can be of great assistance to the speed of trash pulls.
Once more, you've copied a statement from Elitist Jerks without crediting them. The example you use with Desecrations usefulness on Heroic Lich King is obviously not your own, and has no place in a guide for level 70 twinks.
As for RI's usefulness, it brings me to my next point. If your prediction that RI will come in handy in a raid situation holds true, why would you not take Unholy Blight instead? You passed that talent in order to take 1/3 Magic Suppression, which is somewhat of a lackluster talent at 70. A best-in-slot Unholy Death Knight has 21% haste from gear alone, which means we're as good as GCD capped. A single large burst of Runic Power, which can't predictably be weaved into your rotation, seeing as it's dependent on the boss casting a hard AOE has little to no value as such. Unholy Blight actually increases the damage you deal, on top of preventing any dispels that might occur.
You still have a section about Dual Wield Unholy, something I originally suggested to you. DW Unholy has been made obsolete as of 4.0.6, which means this section only clutters the guide. As for glyph choices, do you have any parses or math to back up your statement that the SS glyph beats out Death Coil? If, say, Death Coil was 25% of your damage and the shadow portion of SS was 12% of your damage, DC would be better, but if SS (Shadow) was 13% of your damage in that scenario, glyphing Scourge Strike would be better. With this in mind, you should be able to test it.
Your section about the rotation remains a copy-paste of Considers guide, and is actually an outdated version. You write that we should avoid back-to-back Death Coils, which is actually untrue after 4.0.6, where Runic Corruption was changed to stack rather than refresh itself. I still don't believe you give Consider proper credit. You should note that the whole section is actually written by him, and link to the original post on EJ.
You write that we should pop the Gargoyle while our Ghoul is transformed. Is there any particular reasoning behind this? The ghoul has no direct influence on the damage of the Gargoyle. Perhaps you should also make it more clear not to stack UF with BL.
In your section about gems / enchants, you write that achieving 8% hit is more important that strength, which is wrong. 1 point of strength is worth about 3 times as much as a point of hit rating. Urging people to use hit rating food is therefore also counterproductive, seeing as
strength food results in better DPS.
Your idea of a 35% haste cap is still completely wrong - there is no such thing, and your stat weights in general are completely reversed. You write that mastery is a terrible stat, when it is in fact almost as good as haste. I don't see why you would even mention Mastery in a guide for 70 twinks, but I thought I would point out that what you write is wrong anyway.
Here are actual estimated stat weights. I didn't test these extensively, but since you are posting this as an official guide, I strongly suggest you confirm and update your stat weights:
Strength > Hit > Haste > Experitse = Attack Power > Crit
Unholy Might was changed to a 5% strength bonus, and no longer gives 10% as you write. Also, the Arcanum of Ferocity gives 16 hit, not 17. I assume this is just a typo.
When it comes to the BiS list, you list both the wrong gear and professions. Presenting LW as a viable alternative because you use it yourself is not optimal, seeing as LW is a terrible profession for an Unholy DK. You compare only the sheer attack power benefits, and though you mention RotFC, you don't actually state by how much it increases the value of strength. You also fail to mention that only strength, not attack power, boosts your ghoul. Synapse Springs give strength, not haste, as you claim.
Professions listed from top to bottom:
Engineering > Jewelcrafting > Blacksmithing > Alchemy > Herbalism > Inscription > Leatherworking > Enchanting > Tailoring > Skinning > Mining
Engineering is only valuable is you have the Synapse Springs. Otherwise it is worthless DPS wise.
As for your BiS list, the followings things are incorrect:
Gloves should be
Hard Khoium Battlefists
Gloves should be enchanted with
15 Strength
Boots should be enchanted with
Icewalker
Dragonspine Trophy should be
Berserker's Call
Neck should be
Hard Khorium Choker /
Sin'dorei Pendant of Triumph (if you don't have Jewelcrafting)
I suggest making the Chardev without any professions, since it doesn't clearly indicate which enchants to use if you don't have Leatherworking (which is a terrible profession).
Notes to the above:
If you have Blacksmithing, the
Hard Khorium Battleplate is a better choice for a chest slot.
I have yet to confirm if the
Ancestral Ring of Conquest beats out the one from Illidan. In any case, it is a close call, and it would probably be more convenient to use the Illidan Ring just for the sake of getting closer to the hit cap.
When it comes to trinkets, it has yet to be cleared which one is actually superior for the second slot. Since the 325 haste on DST will GCD cap anybody beyond redemption, and the 40 attack power is very little compared to the passive stats found on other trinkets, it's safe to assume it is not best-in-slot. Since expertise is worth almost as little as Attack Power, Shard of Contempt is in a similar situation, and Tsunami Talisman wasting item budget on 38 crit rating makes it even less desirable. This leaves us with very little choice but Madness of the Betrayer and Berserker's Call. Choosing Madness would allow us to use 32 AP on boots over Icewalker, but the crit proc is worth very little for an Unholy Knight, and the high static AP combined with the on-use on Berserker makes it seem the superior choice - this has yet to be confirmed though.
As for consumables, the Mighty Strength Elixir gives 45 strength, not 50. Also, suggesting that people run with hit food is once again bad advice. Strength food is far superior in any scenario.
You should mention in your section about Icebound Fortitude that it breaks stuns now in addition to providing immunity against them. Perhaps it would also be a good idea to mention that is provides damage reduction as well, which could be used for damage-heavy phases of encounters that don't incorporate stuns.
About DnD vs Scourge Strike on single targets, the home-brewed math you present is actually not proof that DnD is better at 70, seeing as you didn't include the Shadow Portion of Scourge Strike. You should also mention that Death and Decay produces a high amount of threat, something that could be an issue depending on your tank.
You still have a whole section dedicated to dual-wield Unholy, which as mentioned, is obsolete. Your chapter about racials is also taken from Elitist Jerks without you providing a link to their original post, or crediting the original author.
A lot of these things were already mentioned in my original post, but many of these seem to have gone uncorrected. Seeing as this guide is littered with misinformation, I fail to see why it remains in the official guide forum. It should be updated to reflect 4.0.6, and updated to reflect fact rather than guesswork.