i will comment each tree:
1. Blood tree:
- you should get Scent of the Blood, it provides you with 90 RP/min up from only 45 RP/min in the current game.
2. Frost tree:
- dont know about Deathchill, hmm, critical as a tank, hmm. at 2 min cooldown.. hmm
- about Killing Machine, here i might be a bit outdated but i think as a tank, all your melee swings will be replaced with Rune Strike so.. i'm not sure KM will proc at all.. hmm..
- also not so sure about Acclimation too, for a max of +60 RES at 30% chance? hmm.
3. Unholy tree:
- you don't need Epidemic in 3.1, the default durations of frost fever and shadow plague are already increased by 3 seconds i think.. which its enough for a pretty relaxed rotation, so you will have enough time to reapply the diseases..
- Unholy command its kindof.. useless, mobs will be sticky to you anyway if you keep diseases up and constantly blow them away with either blood boil or howling blast.. and you have death and decay which has a small cooldown and also you can enlarge HB and IT range with 10 yards (2 points) so.. really.. you shouldnt..
look what i suggest for you (i think you are wielding a 2hander, right?) :
Hello, we've been discussing a Frost build in another thread, feel free to examine the conversation and contribute:
Anyways, unto your builds
Why skip Scourge STrike? With Scourge Strike, you can reapply all of the dieases in one hit, as well it being Unholy's Obliterate. As well, there's no need for a Ghould - you should focus on your own damage, and not a pet (the pets damage does not contribute to your agro).
Take a look at this build and see what you like.
KIlling Machine (Rank 5) procs 5 times a minute, while Killing Machine (Rank 4) procs 4 times a minute. It basically comes down to a proc every 12s vs. 15s. I would only put 4 points into it, myself.
Since you ended up skipping completely over Blood of the North and not maxxing out Black Ice, I recomend not getting Icy Talons. These two talents are far more important then Icy Talons, which the Imp. version does not stack with Windfury totem.
If your going for Chill of the Grave, also pick up Runic Mastery, to uncrease the total number of Frost Strikes you can do.
Lichborne is next to useless now, so don't bother pick it up.
Look over this build and let me know what you think:
10man Frost tank
This variation includes Imp Icy Talons and Chilblains, because you can't pick and choose the makeup of your raid. 20% haste is a huge boost for other melee in your group. Chilblains is in there as a utility, you could float the 1 point into something else if you like (rune tap, for instance, is always useful). I rarely find myself at 100 RP, so I wouldn't bother with Runic Mastery (macro RS to your other strikes, burns through RP easily).
Many other threads going on this topic, search around.