To get to CttC, I put 1 point in Murderous Intent and filled it out later. I'm operating under the assumption that they will tweak Backstab's damage such that this talent becomes worthwhile (i.e. the DPE of <35% BS is higher than Mutilate). I think this is a reasonable assumption, since the talent is far too deep in the tree to be only a leveling talent, and other classes have similar talents that require them to push a new button in "execute range."

New updates (still from 4 days ago) bu new patch is being added as i'm talking, it means more details real soon :

• Ambush : Ability can now be used with any type of weapon.
  > Level 81 tooltip : "Ambush the target, causing 190% weapon damage plus 642. (275% plus 930 if it's a dagger). Must be in stealth and behind. Awards 2 combo points."

• Expose Armor : Armor reduction bumped down to 12%, but lasts for 10/20/30/40/50 seconds (based on combo points).

• Fan of Knives : Now requires thrown weapon to be used. Cooldown is currently based on the throwing weapon speed. Cooldown affected by haste.

Edit : Talents were updated with combat tree (now showing) : War Tools :: Talent tree Broaclysm Gamma Talents

One consequence I noticed with the move of Blood Spatter and the move/change to Serrated Blades is they have (unintentionally) left Combat with 0 Rupture talents. Every one of it's reachable damage ability talents are for either SS, BS, or Eviscerate. As a consequence, it would currently be the most simple rotation, performing only SS, SnD, and Evis, while Assassination would be performing Mutilate (BS <35%), Envenom, and Rupture and Subtlety would be performing Hemo, SnD, Rupture, and Evis. (Discounting cooldowns in all specs).

We'll likely see some Tier 5 or 6 talent that adds some sort of proc effect off Rupture ticks, like we've seen in Assassination or Subtlety. Those Tiers for Combat are very barren, both of damage talents, and talents in general, due to the removal of weapon specs.

I think it's highly speculative to suggest that combat needs a rupture talent, or that the change isn't intentional. It certainly might be, but it's by no means certain - there's no rule that says that all specs have to use all moves. Personally, I see no problem with having one spec that doesn't use rupture, and frankly, combat is as good a choice in that respect as any. It's true that it may wind up with fewer noncooldown moves, but the fact that it has a lot more cooldowns - and now a talent to improve them - means the spec may not be fundamentally easier to play even if it has fewer moves in it's standard rotation.

Also, in general, we should try to refrain from highly speculative discussion about what we expect Blizzard to do. It's fine to say that the trees in their current form might move combat away from rupture (though without knowing the damage scaling of rupture we can't even really say that). It's fine to observe that this gives Combat fewer finishers. And if there were blue posts by Blizzard indicating that Rupture was an essential ability for all rogue specs, it'd be even fine to suggest that they'll probably fix it. But there's not. And speculating without any basis in fact as to what Blizzard's objectives might be, and/or inventing new abilities to address the theoretical problem, seems beyond the scope of the discussions we want to have on this forum.

To be clear, I'm not trying to single out anyone in particular - there's simply a convenient example here. I'm simply indicating the sorts of discussion that we want to have moving forward - which involves analysis of abilities and the resultant spec/gear/cycle decisions that result, but stop short of attempting to moonlight as game designers in most cases. There's a time and a place for that, but this forum is not one of them.

Given the rearrangement of subtle talents and the addition of some interesting deep assassination talents (specifically, Murderous Intent and Venomous Wounds), it looks to me like the best option is to go for a combat subspec, allowing you to talent into Blade Flurry and Lightning Reflexes, as shown here: War Tools :: Talent tree Broaclysm Gamma Talents
The issue is that out of the 21 points in the combat tree required to spec into Blade Flurry, only 14 seem to be obvious choices. To cover the remaining seven in this build, I took 2/2 in Endurance for the Sprint CD reduction and increased survivability, and 5/5 in Aggression for the increase to Backstab for when we're using it as an execute.

As for a subtlety subspec, it just doesn't seem to make as much sense with the Serrated Blades change. The talents of interest there seem to be Relentless Strikes, Opportunity, Elusiveness, and Dagger Specialization, but the cost in lost talents from the Combat tree such as Precision, Lightning Reflexes, and Blade Flurry seems to be too much of a cost. The only real possibility I see going into the Subtlety tree at all would be this spec, with one remaining floater point: War Tools :: Talent tree Broaclysm Gamma Talents
The advantage of this build would be that in the two trees other than Assassination, no filler is taken, but it'd take some harder numbers on the coefficients and gear stats to say whether the increased Backstab, Mutilate, and Rupture damage along with the RS energy return would cancel out the loss of Lightning Reflexes and Blade Flurry.

I'm inclined to say that the 55/21/0 should be at least comparable to the 56/10/9 (plus one floater point) build for single target fights and better for situations with adds, such as Anub'arak back in ToC, but I don't think we can come to any conclusions yet.

Is there a reason as to why you're not considering a XX/XX/5 build? RS by itself is an excellent talent to take for any situation, and something like 51/20/5 build could be viable as well. Or put 1 point into Blade Flurry and make that 4 RS: War Tools :: Talent tree Broaclysm Gamma Talents

Imp SnD to cover for 2/5 CttC, and barring horrible RNG, you should be able to refresh SnD within 30 seconds before it drops off.

One thing to note about Murderous Intent is that Shred was changed to 50 energy (from 60) two Alpha patches ago. Whether that has any bearing on Backstab is yet to be determined. All three trees are going to get a lot more work, I would expect Combat to get the 'Multi Weapon Hack and Slash' talent back that they talked about in the class update. On the Alpha right now Blizzard has been heavily focusing on Feral Druids and Rogues so there may be some more info shortly.

edit: (I posted too slow I guess, I apologize)

Found these, and the calculator previously posted here has been updated as well: War Tools :: Talent tree Broaclysm Gamma Talents

v12065

Assassination

* Remorseless Attacks now affects all of your abilities.
* Vile Poisons now also gives your Fan of Knives ability a chance to apply the poisons on your melee weapons equal to 33/66/100% of the chance that they would normally apply from your melee weapons. It no longer gives your poisons additional resistance to dispel effects.
* Cold Blood now also generates 25 energy and has a 2 min cooldown, down from 3 min.
* Turn the Tables now also affects opening moves.
* Murderous Intent moved up one row.

Subtlety

* Ghostly Strike removed.
* Initiative moved up one row.
* Honor Among Thieves now only affects physical critical strike chance, only activates on a physical ability critical hit in the raid, and can only grant a combo point every 4 sec, down from 2.

The reason why I wasn't considering, say, a 52/21/3 build was that I was running under the assumption that Rupture and Backstab (as an execute) would both be viable, and in fact desired, in Cataclysm. In the event that one or the both isn't, then you could move either two point from Murderous Intent (in the case that Mutilate still is more favorable than Backstab during the execute phase, or if Backstab in execute is worth less than constant 2/5 RS) or all three from Venomous Wounds (if Rupture is nonviable/worse than 3/5 RS). I'd be extremely leary about 2/5 CttC, though.

For some rough math, neglecting the effect of Focused Attacks and assuming you put 2/2 points in Imp. SnD, you'd regenerate 315 energy over the course of the Slice and Dice's full duration. Assuming perfect luck with Ruthlessness and Seal Fate as well as the 4/5 RS working every time, you'd be able to pull off four Evenoms (4 x 55 (Mutilate) + 4 x 35 (Evenom) - 4 x 25 (RS) = 260, leaving you enough for an additional Mutilate but not the following Envenom).

Given that we now have the variables required, we can determine the probability that this will fail to proc CttC. The variables needed are the probability (p) of the event occurring on each attempt (40%), the number of attempts (n=4), and the number of successful attempts (s=0), we can use the equation P(s|n) = n!*p^s*q^t / (s!*t!), with t=n-s and q=1-p. Given that in the circumstances described, n! = s!t! and p^s = 1, this reduces to the P(0|4) = (1-0.4)^4. This gives us an approximately 13% chance that 2/5 CttC will fail to proc on four Envenoms during a 31.5 second Slice and Dice, and that's assuming pretty much ideal conditions for this to work. I'm not in favor of a rotation that has a 13% chance of collapsing, though going up to 3/5 CttC lowers the chance of CttC failing to proc to 2.56%, and 4/5 to 0.16%.

At that point, though, I'd probably just take the surety of 5/5 CttC over 4/5 CttC and 1/5 RS, especially considering that I'm ignoring the fact that RS will not necessarily proc especially with fewer points put into it (with 1/5 CttC, for example, you have over a 50% chance of RS not proccing even once, limiting you to three Evenoms, and which would increase the chance of 0 CttC procs to 0.8%) and that you likely won't have the perfect rotation of one Mutilate per Envenom assumed in this math, especially with the lower crit rates we're likely to see in the expansion.

It hasn't shown up on the alpha as far as I'm aware but we do have confirmation that Hunger For Blood is gone in Cataclysm.

World of Warcraft - English (NA) Forums -> Hunger For Blood, Going away in Cata?

Given that a good deal of the Eclipse debacle, if I understand it right, was that it made Haste's value drop off a cliff after reaching a soft cap for Wrath, I can't see it being quite the same. Really, it seems to me that the priority list for a Subtlety build would just be this:
1. Keep SnD up.
2. Keep Rupture up.
3. Eviscerate when possible.
And occasionally, when the RNG favors you, #3 helps with #2. When RNG doesn't favor you, you'd just end up with something resembling a high rupture rotation.