It appears that Darkmoon Card: Hurricane does not have an internal cooldown. I wonder what the results would be if a DW frost death knight prioritizes haste above crit plus unholy presence. If the proc goes from 2-3 procs per minute to 4-7 procs per minute by doing this, that would be very nice.

Kregolich seems to have narrowed down the issue with haste and the simulator, over in the sim's thread, at least to an extent. Whatever else, he's managed to prove it exists, although it was obvious enough previously due to the exorbitant values. I miss the old version of the sim; the silverlight one has been more problematic, it seems. There's a bug; to not take it into account is just willful ignorance when it's clear as day that something is going on. I'm sure Kahorie will narrow down exactly what's causing it and fix it as soon as possible, but there's no point in going off a tangent of theorycraft which is based off a program acting up.

At any rate, his results closely echo mine; haste is still a bit higher than I have it, but lower than crit, and that's likely because Kregolich is using his own gear, which has a mere 3%; in full 359, it would simply come down.

Anecdotally, I would bet a lot of the reason people aren't feeling as GCD capped as the spec may be is because of the undocumented but easily noticed bug of runes randomly jumping back half a second or so, on top of their treatment of RE; a factor of play which has been discussed surprisingly little. The rune bug is pretty clear, and a huge factor as to why Frost is underperforming relative to Unholy. As to RE, although, yes, using procs instantly for DnD/HB/BS is faulty behavior, so is using procs for nothing more than Obliterate/BS. In reality, sometimes you want to do the first, and sometimes you want to do the latter. It all depends when RE procs; a HB + DnD does outdamage an Obliterate (ignoring KM, that is), but the additional GCD cost of the former, in addition to the lack of Rime, makes it fall behind in a vaccuum. If RE procs a single Unholy or Frost rune where you'll have empty GCDs following it because you'll have no other runes up (or two of that type which just procced) and sub 32 RP, you are better off using one of those two spells, since the globals would otherwise go to waste. On the other hand, if RE procs and you can still do something else, it's more ideal to leave the proc sitting, do the other stuff you can do, and you'll likely be able to Oblit once you get around to using that specific rune.

In terms of the sim, it's much easier to think of: You would set your priority as Rime > Frost Fever > Blood Plague > FS Max RP > Oblit > BS > FS > HB > DnD > BT > ERW. Basically, it will do your rotation as normal, but DnD/HB when it can't do anything else. Very easy to see that it does result in more dps, as logically makes sense, although in actual play there's some situations where you would hold off, of course, which the sim isn't smart enough to differentiate.

But, yes, there will always be times where you run into GCD gaps, just as there will be times (the entire duration of Heroism, for instance) where you can't use them fast enough. Overall, however, the spec uses the vast majority of its globals without gearing/reforging for any haste, or at least would be if the rune bug wasn't around, and thus I still hold the stat is weak for the spec, and the objective proof seems to back me up. If you believe differently, you are of course welcome to gear yourself as you will and argue (with some sort of support, of course) otherwise, but I don't see any need to change anything here (although I could touch up the wording, yes) based off the lack of (faultless) evidence to the contrary provided so far.

The rune bug is the real thorn in the side of this issue; I would just math around it since it doesn't seem like it will be fixed any time soon, but I've yet to see (or been able to determine myself) what causes it to happen, and exactly how it works.

A bug I assume, but it should probably be mentioned in the OP: The paper doll doesn't appear to reflect the yellow hit required for Nerves of Cold Steel (i.e. it shows 8% required vs. skull, rather than 5%)

So what is this I hear about DMC: Hurricane not having an internal CD? Where would that place the trinket in comparison to the Valor-trinket and BRC-trinket?