I'm not convinced as to the lack of threat using two fast tanking weapons. I recently switched to DW frost tanking from 2-handed frost tanking. I picked up two Rimefang's Claw from heroic PoS, put nerubian carapace on them, and my threat is better than ever. Even with three heavy dps'ers in my ten man raiding group, I rarely, if ever lose aggro now. *shrugs*