I've only been tanking as a DK for less than 2 months so I'm a complete n00b on the pros and cons. :-\
Question 1 = Bad idea to remove Rime? 15% chance for a free Howling Blast, doesnt proc often enough for me. 1v1 tanking, I normally use:
DnD > IT > SS > BS > FS (Rune Strike whenever) > Tap > BS > OB > OB.
Personally, losing the chance for a free HB doesnt seem like much of a big deal to me since I hardly ever see it proc. Question 2 = But would the 15% crit make a huge diff?
I am hoping that with DW tanking, I will get to pull off more Rune Strikes to hold agro cause atm, 2H as you know its slow, therefore Rune Strikes dont hit fast enough. I will be using two of the 5-man H ToC tanking sword.
Question 3 = How much hit would I need while DW? With 2H atm, I have almost 9% hit and about 7-8% Expertise.
Any comments or suggestions to help me pro up the spec would be greatly appreciated.
Rime is a good talent in my opinion because 15% crit on obliterate is a nice increase in threat, and you have the gc to use the proc when it happens. So when the proc does happen it is 100% extra damage.
You can easily get the pts for Rime from Lichborn, Deathchill, and Hungering Cold.
Lichborn has too long of a cd to be useful. On the fights that it would be useful, the effect happens often enough that you'll have to use it anyways.
Deathchill: while having the additional burst threat at the beginning of a fight, it is not necessary.
Hungering Cold: Very rarely do you CC in tanking environments. Thus this just lets you get you disease out quicker than IT+pest
DW is all about expertise, and having more avoidance because of tanking weapons(or agi on dps weapons). Your expertise and hit are fine for DW.
I think that your glyphs are your weakest point. Glyph of Disease, and Glyph of Obliterate would go a long way to improving your threat.
Glyph of Disease lets you trade the IT+BS for an obliterate, at the cost of a blood strike. This will also result in more rime procs.
Glyph of Obliterate: Obliterate is one of the largest sources of damage to a frost deathknight, thus you should improve it over other options.
I would drop HB and DnD for those glyphs. HB for the same reason as Hungering Cold. DnD because you should never have issue with AoE threat as a frost dk.