>If we're assuming a non-flying non-arial thief, sure.

Even if he's flying, you can go for the strangle + blind dust or murder then blind right after when he walks back in (usually works pretty good if you time it right). Its not easy, but still, it'd be pretty hard for them to get you blinded, slowed, steal all your stuff, etc etc etc etc too. I don't much see point in saying 'how good are things when no one defends against it or makes a saving throw' because if that's the case APs and Necros are unstoppable.