As I am not a member on this forum who gets into mathematics, does number crunching, or actually gets into Death Knight Tanking all-together, I can only help so much. On top of that, the best results you are to get from tanking is experience and experimenting.
For as long as I have been tanking, the best tank is one who learns knowledge from observation, and pure research. So I will try and help you as much as I can, but the rest you should try by yourself.
Since recent patches, Parry + Death Knights has been diminished. Avoidance overall for tanks has been reduced, for diminishing returns have been put on them and one second you're doing fine and the next you drop to almost 10% health and make healers shit bricks, so it's wise to try and stack as much Stamina + armor as a death knight as you can.
As far as your glyphs go, I'd say get rid of the major ones that cause threat for a Death Knight always causes excellent threat. Get something that helps reduce damage done, or reduces the cool down of a helpful ability.
And for talents, it seems that you should try and move a lot of them around. I see many death knight dps who go frost / unholy or blood, so the Icy Talons is not needed. You should try and put those into the 5% dodge in Unholy, for even though avoidance has been reduced for Death Knights, this is some that won't go into your gear and hinder your health + armor, and can help you survive longer. That or put it into Toughness for armor is extreme mitigation and awesome for Death Knights + any tank for that matter.
Also, I'd move your points out of Butchery in the blood tree, and place them into Two-Handed specialization. This will cause more threat, generate more Runic Power then you get from Butchery, and help dps over all.
The rest is there for you to decide, but I'd suggest keeping your mind open to the Improved Frost presence, and other talent points that can reduce the damage done to you.
The reason behind this is that compared to a warrior or paladin tank, you have less armor and no shield block. Druids have to put up with this too, but they get the extra health bonus and armor, and do not require defense.
Overall really, Death Knight tanks got screwed over and it requires a diligent mind, proper gearing, and correct rotations to actually play one well. Since they have no boost in armor, a shield, or health like other tanks, it requires them to have to get their gear higher, stack stamina, and get as much armor as possible to do well.
So I hope what I said helped in some way, and I'm sure someone who actually plays a very good Death Knight Tank (if any), will drop by here and give you a much better response than mine.