In the patch notes for 4.0.6 currently on the PTR, there are two relevant changes to combat dps…
This is a nice change. One of the big knocks against combat’s Mastery (Main Gauche) is that when it procs it gives an extra off-hand attack. Since rogues are forced to use fast off-hands (for Combat Potency and poison application) our off-hand is always a much lower damage weapon than our main hand. Thus, the Main Gauche proc was always underwhelming, and Mastery was a weak stat for combat rogues.
If this change goes live, then the Main Gauche proc will give an extra hit from our slower, harder-hitting weapon. That should make Mastery more appealing and more useful to combat rogues.
(2) Revealing Strike now increases finisher effectiveness by 35% (45% glyphed), up from 20% (30% glyphed).
This is a straight damage buff. The theorycrafters at Elitist Jerks estimate this as about a 1.5% increase in combat dps.