The Assassination tree, home to the deep dagger Rogue, is a major part of Rogue specifications for both PvP and PvE play styles. While the Combat tree is focused on increasing white damage overall, and Subtlety about survivability and burst, Assassination is all about the liberal application of consistent damage through a repertoire spells and damage application modifiers (a la poison). Burning Crusade talents and spells like Cold Blood, Lethality and (Improved Poisons assisted) Envenom are amazing non-positional damage sources, with Mutilate being the positional coup de grâce to a fight.
All that said, it should be noted that while Assassination Rogues do benefit from three times the combo-point generation potential, white damage is reduced in comparison to other builds, most mobs in end-game are poison immune (and in situations where you need to change targets, you have to build back up your poison stack on them) and Find Weakness does not apply to white damage.
Knowing all this, what's new that might make wayward-but-dagger-longing Rogues want to go deep into the tree?
The seven new talents in the Assassination tree are: Deadly Brew, Turn the Tables, Infectious Poisons, Blood Spatter, Cut to the Chase and Hunger for Blood. The new talents start at the seventh level of the Assassination tree and require a commitment of at least 30 points (out of the possible seventy-one at level eighty).
Poisons can be the bane of the Assassination Rogue, either providing a huge benefit in damage or utility or being completely unavailable due to current boss game mechanics (in that they are immune). Both Mutilate and Envenom require poison applications on the target to be in any way useful (Mutilate gives a 50% damage bonus against poisoned targets). Assuming that you've got yourself a non-immune target, Deadly Brew would give you a 50%/100% chance to apply an additional, non-equipped poison(!!), to the target. Instant Poison will apply Deadly Poison (in addition), Wound Poison and Mind-Numbing will apply Crippling Poison (in addition). As you might expect, this provides a great benefit in PvP since now you can apply Instant and Wounding to also get Deadly and Crippling. I'm already hearing cries of "OP." Combined with Improved Poisons you'd see the stacks build fast. Obviously PvE viability would require a change in the way poisons work on boss encounters.
Continuing on the poison train, Infectious Poisons increases the damage of Instant and Deadly poisons by 20%, and when fully talented, give a 100% chance to apply (or infect) the healer/dispeller. So, now you've got Deadly Brew that will passively get you Deadly with Instant poison, Improved Poisons that greatly increase the poison application likelihood and Infectious that will, 100% of the time, transfer the debuff to the healer. Wow. Talk about a chain of talents designed for a PvP environment. I wonder though who would get the debuff with a poison cleansing totem? Surely Blizzard is trying to drive a wedge in the deep Subtlety builds for PvP through the use of these talents, driving more dagger specs down that path. As a deep Subtlety Rogue myself, who has been visiting his daggers in the bank, this may be the talent chain that brings me back.
There are several passive benefits that rogues can acquire in groups (Ferocious Inspiration comes to mind), and now we have another in Turn the Tables. Any parry, block or dodge in your party can grant you a 2%/4%/6% chance to critically hit in "combo moves" (which I read as any move that generates a combo point or a finisher). I love this talent, I think it gives rogues the additional burst damage output potential that may have been lacking. Traditionally I dislike abilities that have a low chance rate, but I'd be willing to give this a spin in starter encounters in the expansion to see how well it shines.
Effective finishers in the tree come down to either 3-5 combo point Rupture or Slice and Dice. Blood Spatter adds 10%/20% increase in damage to your Garrote or Rupture, an interesting choice in such a high-point talent. I would have expected something more in line with resilience or armor reducing to get back dagger utility, or even a talent that let you use a positional attack (e.g. behind) in a non-positional manner one time, a la the crit enhancing Cold Blood ("your next attack that requires you to be behind the target can be made from any position"). I'll take the damage bump since I'm a religious Garrote/Rupture'er, but it's less than what I hoped for.
Focused attacks, on the other hand, is a very nice deep build talent that will give you give you back 1/2/3 energy on a 30% chance for any critical strike you make, white damage included. This is great for PvE as well as PvP, and with the change in energy regeneration rogues with high crit should see a vast improvement in energy availability. Combined with Seal Fate, which adds combo points for talented crits, you're in a great position to have both points and energy for finishing moves, which in turn can net you a 20% Blood Spatter bonus. I'm seeing a lot of great synergy here within the tree, providing an excellent payoff for Rogues who decided to invest deeply.
Cut to the Chase is a little more involved. There's been a lot of discussion about it on the Wrath beta forums a little (you can read the entire post by Vulajin), but in essence the ability, which allows you a chance to sustain your Slice and Dice at the five point level with a critical from Eviscerate or Envenom. This proves to be a downgrade in finishers than just a Rupture overall. Apparently the people who have theory-crafted this have determined that Cut to the Chase is worth less in overall theory value than a Rupture in the same casting cycle by quite a bit. I'd like to see it for myself, but the argument that this new ability doesn't fit well in energy/combo cost as compared to something we already have, is disappointing.
Our final new talent to discuss is Hunger for Blood. Hunger is a non-passive talent that buffs all damage by 5%, removes one bleed or magic debuffs and refund the energy cost. It can be stacked 3 times and lasts 10 seconds. At 30 energy a pop I have trouble seeing where this talent fits in properly, especially when you consider the overall rotation costs of Mutilate builds. 30 energy for a 5% increase in damage when energy generation per second is too slow to support it is problematic.
All in all I am pretty excited about the new talents, even if I think a few of them need a little more work before the release of Wrath. I'll readily admit that I'm not a super theory-crafter and Cut to the Chase and Hunger for Blood potential may be a little out of my paper-and-pen league to determine how much they help/hurt. Somewhere out there is my beta invite (Blizzard, are you reading this? wink-wink), and I'm really looking forward to testing these (and the other changes) out.