Back towards the end of Wrath, Blizzard shared with us a lot of information about the then-upcoming Cataclysm expansion. The new 31-point talent trees were unveiled, along with the mastery bonuses for each tree. The mastery bonuses were heralded as the ultimate balancing tool: Developers could tweak these numbers without touching a tree's talents. Mastery would ensure that any given spec could be tuned independently of the other specs.
The concept made sense, as buffing individual talents had a tendency to cause players to just cross-spec into those newly powerful talents. The other option at Blizzard's disposal is buffing talents that are deep in a talent tree, which works well since we can only go 10 points deep into our secondary trees.
In order to buff rogues in the upcoming patch 4.2, the developers have used both approaches. Our assassination and combat masteries are both being buffed by 5%. Deep talents in each tree, like Vile Poisons, Savage Combat, and Sanguinary Vein, are also being improved. Finally, subtlety rogues will see Hemorrhage's base damage improved by 40%, although it remains to be seen how this change affects the spec's viability.
Even with these buffs, combat and assassination rogues are still slated to be well behind most other classes. Rogues are generally middle-of-the-pack in DPS for most tier 11 bosses, and these changes will just make us "less behind." Other classes might ask us why being "average" is so bad. Average might be okay for a hybrid, but rogues need to top the meters -- not for our egos, but by design.