Well I'm not sure what you'll be using pre-double dagger (the arena ones right? those are a ***** to get) because even questing at 70 can yield mcuh better weapons then the ones you have. I got a 71 dps sword the first day I got 70 from botanica. If your planning on going 2 daggers all the time though you should definetly go full mutilate. It is amazing. When the patch re-spec comes, there will be no imp sap to get since all rgoues will have it, so go full assas. to get mutilate, 3 points in imp SS, and 3 points in imp ambush (i think this is possible). That would make you great in pvp.