Now, I have't fleshed this idea out fully and it certainly needs more balancing and the numbers are all there for the sake of being there, but I feel like doing something along these lines could spice up the Combat spec and fix some of the scaling and downtime issues it has.
I think we can (almost) all agree that combat has some extremely boring parts to it, especially early on in an expansion and even later on when not inside AR. The cost of Sinister Strike makes gaining combo points outside of Adrenaline Rush very slow, Adrenaline Rush scaling so well with haste also causes haste to be extremely valuable and causes some scaling issues where there's a bit too much disparity between fighting with and without Adrenaline Rush activated. Granted, AR does have its cooldown shortened every time you use a finisher, it still seems to be an unnecessary difference between uptime and downtime in abilities. Now, what if Adrenaline Rush was made a passive ability and the combat rogue was given a choice in varying playstyle?
The idea stems from Frost DKs (and Fury warriors to a lesser extent) differences of gameplay and gearing when using a different weapon(s), so what if they extended a similar mechanic to combat rogues and their OH weapon choice of a slow sword/axe/mace/fist or a fast dagger in the off hand slot.
This is where it gets into changing things:
Increases the rogue's base energy regeneration by x%(50%?) and attack power by 40%
Slice and Dice and Rupture have diminished effects baseline for the spec (modifiers below)
>While a dagger is equipped in the offhand slot, Slice & Dice's effect is increased to 60%, Sinister Strike costs 15 less energy and Main Gauche attacks restore 15 energy (5 second icd)
>While a sword/axe/mace/fist weapon is equipped in the offhand slot, Sinister Strike deals 25% more damage, Rupture's effect does 100% increased damage, Eviscerate and Rupture have a 15% increased chance to critically strike. Rupture and Eviscerate critical strikes restore 25 energy (5 second icd).
This is just a rough idea, but I with this method, a dagger OH would be likely to favor Mastery/Haste > Crit and a slow OH would favor Crit > mastery/haste.
I was thinking of ways to make the play between Revealing Strike and Sinister Strike more interesting and engaging instead of Revealing strike simply placing a debuff on the target, but it seems they are toying with that already and I'll wait to see how it ends up.