Well I finally hit 90 today and I feel weaker than ever as assassination. It probably takes me a good 30 to 45 seconds to take out a mob. I figured it must be my daggers so I ran Arena of Annihilation and got a the 450, then I did a quest and upgraded my other dagger to a 347. Still feeling super weak. When I compare my rogue to my friend's fire mage there's like no comparison. He can take out mobs super quick, and I feel like I'm watching paint dry.
So is this a common experience for rogues? Or just mut? Should I spec something else for questing/dailies?