There's reason to believe that Mongoose passes Berserking, and most estimates show that Black Magic passes both for the OH. Though it might be worth verifying that Black Magic still procs off poisons - I've heard people assert both that it does and that it doesn't.
I checked it right now (PTR Version 4.0.1 (13156)) and it still procs off poisons:
Since I use the german client here is a little translation:
Maybe it's also worth noting, that I've been hitting the dummy for about 5 minutes just with DP, while reapplying it with shiv, and Black Magic procced only when I applied DP, but not off the DP ticks.
1) Considering H: DBW, the passive bonus is only a little better (+17 crit), but H: DBW has 2 procs out of 3 that presumably might be better than H: STS (700 haste, 700 agi) and the third proc is not too far behind H: STS (1400 instead of 1472). In fact H: STS should be reasonably near H: DBW and it might even be a little worse due to how haste and agi procs overtake H: STS 's. The last point is quite subjective.
Key thing to note, though, is that STS has better uptime (33%) than DBW (28%), such that in practice it tends to be better despite proccing a weaker stat.
Regarding trinkets in general: that ordering was based loosely on some calculations one of my guildmates is doing with a heavily modified version of my Mutilate spreadsheet. He's continuing to refine his adjustments, so I'll probably be changing that trinket ordering in the next day or two to match what we find.
As an aside on HWT: note that that rating is based on fights like Festergut and Saurfang. On a fight like (for instance) LK, it'll be quite a bit weaker than that.
With Assassination spec. I would rather take Deadened Nerves for better survivability instead of
the point for crippling poison(Deadly Brew). Most rogues use a weapon-swap macro for the crippling poison occasions.
Crippling on the thrown weapon is how I dealt with it in beta. Longer range and more control, also remember that weapon swapping won't do any good for FoK since FoK uses your thrown weapon only.
In Sub spec wouldn't Initiative be a better fill spot instead of premed and Enveloping Shadows? Solely because it will be useful during Shadow Dance, as opposed to once or twice per fight as premed would. Granted none of the three are great choices, but a more useful filler perhaps?
Keep in mind that Premed is usable during Shadowdance, and is off the GCD. Premed will see a lot of use as a sub spec.
As for reforging, you definitely want to do Crit -> Haste if you are near BiS. I was harshly crit capped when I copied my character to PTR, even after replacing all my shiny new crit gems (...) with agility.
I was able to replace 238 crit rating with haste, which helped a lot, and also offered other gem choices besides 20 hit on blue sockets (even to the point where a single 4 agility bonus wasn't worth a blueish gem anymore).
And wow, is Herkuml really that good now?
I was crit capped as well, I guess I just dont know if its better to to reforge the majority of my crit to haste OR if I should reforge first and foremost for hit\expertise cap, then reforge the remainder as haste?
With Reforging, and the Values changing what is an acceptable Miss % range for 83+ mobs?
Reforging mostly haste will bring you far from white hit cap.
Made some edits based on discussion and feedback, as well as more detailed information about stat/trinket weighting for assassination based on continued research on that topic. If you see problems, let me know.
Those EP values don't seem to be internally consistent. Consider:
H:DV has an EP of 250, while HWT is 238. So H:DV is 5% ahead of HWT.
HWT provides a static 153 haste and 340 AP; hence, the EP value should be roughly 153*2.25+340 = 684, while DV has 33% uptime of 510 Agi and 288 AP, which works out to an EP value of .33*510*2.88+288 = 773 EP, which implies that Verdict should be 13% ahead.
Berserking and Mongoose have equal uptime. Hence, the comparison is 400 AP vs 120 agi and 30 haste rating (which is what Mongoose now gives). Pulling (say) the Assassination EP values, we have 120 * 2.8 + 30 * 2.2 = 336 + 66 = 402 EP for the Mongoose proc. Plus one raises your defensive stats while the other lowers them. That is: they're very very close, but Mongoose is currently looking slightly better.
Note, however, that Black Magic does not have the same uptime, so the same comparison does not apply.