Welcome to the Death Knight Simple Questions thread. This thread is for all your simple questions which you expect to have simple answers and thus do not require their own thread.

Note that all forum rules still apply: we said simple questions, not stupid questions (which have no place on these forums). You're still expected to make a reasonable effort to find the answer yourself by searching and reading the threads and making use of spreadsheets and any other tools that may be available. If, however, you're fairly confident that your question is not easily answered with available information, but don't think it will generate sufficient discussion to require it's own thread, this is the place to ask.

It rounds down. I tested this by going through my gear. For example, [Necklace of Black Dragon's Teeth] has 167 crit, which I have reforged to haste - giving me 66 haste. 167*.4 = 66.8. I checked a few other pieces to make sure and they all rounded down also.

Missed(messed up) at work the blue post that says that Army won't loose it's cool down before every boss pull, but rumors are telling that it was already answered. Can someone link that blue post about army won't get refresh after every wipe/before every pull or we still have some hope about it?

Fortunately, the post you are referring to was superseded shortly afterwards by another blue post which confirmed that the decision had been reevaluated. Cooldowns such as Army and Empower Rune Weapon will benefit from the reset technology in Mists.

For reference, here is the original post stating that it wasn't going to happen: Beta Class Balance Analysis Pt. II - Forums - World of Warcraft

Here is the later post that described the change of heart: Beta Class Balance Analysis Pt. II - Forums - World of Warcraft

Corpse Explosion currently does no damage.

For unholy on live, crit currently has a higher value than mastery, unless you are using gurth. Will this still be true when soul reaper comes into the mix for mists?

No. Crit will outweigh Mastery in Mists (assuming no changes), since Soul Reaper benefits from both.

The cooldowns being reset after every encounter is something that will come when pandaria goes live. Two weeks longer isn't too long to wait.

Just curious but in regards to spec performance, how are the specs simming against each other in terms of level 90(DW Frost/2h Frost/Unholy). Percentage differences would be appreciated.

2h frost > dw frost > 2h unholy.

You can always find the latest sim results and compare for yourself at SimulationCraft

However, there's a lot of information missing from that picture. They're not being deceptive, and they do an incredible amount of work to ensure accuracy. But it is what it says it is -- a pure single target dps burn against a Patchwerk-style boss with no movement requirements, no "stop dps" phases, no aoe opportunities, and in general, no encounter-specific changes to increase or decrease your damage. We haven't had a true Patchwerk boss since, well, Patchwerk.

So you can refer to a ranking like that, but also keep in mind what you know about the classes and specs represented, and consider how they will fare in the fights you'll be working on. DW Frost is stronger than the ranking suggests when there's a lot of adds or movement, since HB is so much of your damage anyway --- but when aoe and cleave can be risky or harmful this becomes a disadvantage. Unholy is stronger than it appears on paper when you spend a lot of time out of range of the boss (including out of HB and Siphon range), since diseases and pet damage can continue -- but like other DoT and pet classes has to pay extra attention to "stop dps" timers.