I actually used a few arguments against that on the WoW Rogue Forum. I meant my comment that SnD is only one ability to click every 36s.
The worst thing I pointed out was that Assassination rogue will be balanced around it. The burst will be weaker if you don't have it and for doing maximum you'd need to put garrote, rupture and SnD, making it harder to swap especially in the PvP environment.
I, of course, don't mean that you won't be able to, because mostly you'd have to use a few GCD and putting rupture and SnD would be kinda stupid. But it's a situational problem.
I'd be still able to play PvE and PvP fine, it's not a game-breaking thing(I was playing with it before without any problems). I just find that ability boring and bland. Most of the time it seriously is a button that you click once in 36 seconds.