The reason that BM is more latency friendly has very little to do with the ratio of instant cast and cast times shots that BM does relative to the other hunter specs.

It has to do with the fact that the BM pet does 3 to 4 times the damage of the pets for MM and SV while the BM hunter does considerably less damage than the MM or SV hunter. Since most of the pet attacks are much less affected by our button pressing and are done automatically by the pet AI, pet DPS is a lot less affected by latency than hunter DPS. Regardless of whether the BM hunter does more instant cast abilities than the other hunter spec or not, the hunter damage is so mcuh less that the affects of the latency is less transparent since it is affecting a smaller amount of the DPS.

For those looking for level 85 numbers, I ran a simc report using the latest version with T13H profiles and posted it at:
Simulationcraft Results

I did 2 versions, one with Lynx Rush and one with Murder of Crows (both versions used Dire Beast). I set the race to worgen so that orc pet bonus wouldn't throw off the cross spec comparison. Obviously this is a sim and not necessarily reflective of real performance, but I know a lot of folks have been looking for data about level 85 specs. According to the sim, the difference between the specs is extremely small.

It is kinda strange (and good) how all 3 specs are that close together. It also seems a little odd how haste overtakes every other stat by a lot, when it should be bottom at least for SV and BM since we will use less cast-time shots on every spec.

Haste doesn't overtake every other stat for BM, it is dead last (ignore the valuation given, and switch out other stats for haste, it is a loss) - haste doesn't do anythuing significant for BM thanks to Focus Fire (40% haste with what should be ~50% uptime) and the fact that to fit in anything more we need to be at 33% haste for 1 more instant in 2xCoS cycles, and 100% haste (1 sec casttime CoS) for another instant in a 1CoS cycle without delaying KC.
Figuring in latency we need a little less than that, as we can delay KC by 0.3 seconds without a loss of dps - thats 0.3 real seconds though.

I´m Sorry, I was talking about the lvl 85 sim Rivkah posted, not actual beta numbers, thay may have led to the confusion.

In the lvl 85 sim the stat priority is the same for all 3 specs:
Stat Ranking Wdps > Agi > Exp > Hit > Haste > Crit = Mastery > AP

While in SV the difference is small (2.1 haste 1.9 crit) for BM and MM the gap is a lot higher, 2.8 to 1.8/1.9

I am fairly certain that the value of haste given in the valuation has to do with shot shifting and at certain ponts a specific amount of haste will give one more AS over a CoS or including a KC more over the simulation due to the way the priority works, and the non-linearly valuescaling of haste.

Also keep in mind that Dire Beast scales with haste, so it's possible that certain haste sweet spots are reliably giving extra hits and more focus, which could be translating into additional dps. BM also has less pet focus regen than it used to, so more haste may be giving the pet more wild hunt uptime.

Looking at simulationcraft output, the expected uptime in high end gear and raid buffs for focus fire is somewhere between 40-45%. Due to the weakness in pet regen, it would be lower in dummy tests or other non-buffed environments (fervor would probably bring it up a bit if your pet is having trouble keeping basic attacks on schedule).

This would justify having as much crit as possible then? for increased GFTT procs? By the same token would not haste have a knock on effect of increasing autoshots and increase focus regeneration passively.

The fastest you can realistically expect the pet to cast his basic attack is roughly every 3.3sec (due to latency and the cooldown). So to maximize focus fire uptime you'd want your pet's focus regen to be high enough that he can keep that up (taking into account that bursts of focus such as those received when you activate focus fire will be turned into wild hunt attacks so it's possible your basic attack uptime may be choppy).

Both crit and haste increase your pet's focus regen in different ways (go for the throat focus will be more bursty and may produce more wild hunt attacks, haste is a smaller more consistent increase- this is ignoring the comparative value of the stat buck). Once you have sufficient focus to keep your basic attack uptime to maximum, there's nothing you can do to increase your focus fire uptime, since there's still a fair amount of RNG involved in the frenzy proc.

I've run another simc report for reference at level 85, which includes the various talent mana tree talents for all specs, as well as several variations for SV which skip explosive shot except for during LnL procs. Details at:
Simulationcraft Results

This doesn't reflect the rabid nerf announced today, which should drop the value of LR, especially for MM/SV. But it should be noted that the simc which uses dire beast + explosive shot on cooldown and the version which uses thrill and explosive shot only when LnL procs are virtually identical in damage. This does not hold true in level 90 sims but in level 85 sims with the 2pc T13 bonus it seems to make very little difference.

Update- I applied the snake trap and rabid changes to my site. This removed the benefit of keeping snake trap in a rotation.

Here's my before and after results using the T14 normal gearset that simc is using (I've switched from using the T14H as this one is a bit more relevant):

BM before: 91490.73 (DB/LR/GT) after: 89314.37 (DB/LR/GT) - Zeherah's Hunter DPS Analyzer
MM before: 86220.59 (DB/LR/GT) after: 85373.95 (DB/MC/GT) - Zeherah's Hunter DPS Analyzer
SV before: 82594.47 (DB/LR/GT) after: 82475.14 (DB/MC/GT) - Zeherah's Hunter DPS Analyzer

Note that although my site was showing MC above LR before, I was using LR because that's what simc was using (simc was seeing it higher due to rabid stacking). I switched to using MC after since I'm presuming LR will no longer be higher in simc after the change, although I haven't checked yet.