Okie dokie, if you're looking to prune/adjust the tree, here's what I'm thinking:
1.) Chill of the Grave is too good to leave off, in my figuring, which normally I'd say is for more frost strikes, but also I'd point out it's nice to be able to bump up your RP quickly for a Mind Freeze or IBF.
2.) Hungering Cold and Icy Reach are both nice, however the first is highly situational, and the latter is really more of a convenience (wouldn't expect your to be doing wide area HB's anyway, since it's wasted on stuff without Frost Fever which means you need to collect them anyway). Either or both of those could be traded off. Your build has plenty of good mitigation and I'd expect you're on the sunny side of threat potential for a DK tank, many people trade off a LOT more dps talents for the sake of splitting trees for survival.
3.) I love Killing Machine and I miss it terribly when I'm tanking as Frost, but the cold hard truth is, even if you have dps weapons with strong amounts of Crit on them, you're not going to be much past 10% crit, and that's only if you're lucky. As such, even with dual wielding Killing Machine isn't going to give you the same value you'd like it to. That's 5 pts that while it may hurt your sensibility to move will probably give you more elsewhere.
4.) I love Lichborne in concept, 25% avoidance is pretty huge, but the 3 min CD means I tend to shy away from it in favor of digging deeper into my secondary tree (where I can actually benefit from that one more point of course).
5.) I understand why you took Morbidity. I have found the same desire when tanking as frost to have some steady aoe threat to count up while you setup your big HB threat spikes. At the same time, I think you can probably get more out of leaving DnD out of all but the most situational fights in favor of saving those runes for more frost-style threat. If you want to get your burst off sooner, I'd suggest only setting Frost Fever and quickly Pesting to get it around, immediately followed by your HB. If you juice it with Deathchill you won't miss the DnD baseline threat at all.
So, if we leave Lichborne, but prune out HC, Icy Reach, Killing Machine, and Morbidity, and add-in Chill of the Grave, you have 9 points freed up for other things. Personally I'd put them into Bladed Armor and Rune Tap (the healing is quite nice for life extension and having a more-than-just-emergency health spike at your control). And I'd put the remaining 3 points into Scent of Blood (again, more RP is good, and it'll go off pretty frequently), Annihilation (3% crit on Frost Strike and Death Strike is nice), or Ravenous Dead (3% strength is threat and avoidance, and it scales very well with endgame tank gear). My personal taste would probably be Ravenous Dead > Scent of Blood > Annihilation, but that's really a matter of personal choice.
Alternately if you want more survival, I'd highly recommend putting those last points into Frost Aura and/or Acclimation. Spell damage is not at all a situational affair in Northrend. It's a very rare fight that has no spell damage being passed around. Remember, these resistances apply to anything that's not strictly physical damage, not just "spells."