If I remember correctly, the world record for a smash is with the Yonex Arcsaber Z Slash. Which is stiff and head heavy. I don't know why you even brought up those other players. Lee Yong Dae uses the BS09 yes, but he's the tactician in the doubles team. The smasher is Jung Jae Sung and he uses the SW35. Which sort of backs the notion that head heavy stiff rackets are more ideal for power or smashes. That's not to say he has a better smash BECAUSE of the SW35, but that because he's a power player he's more suited to the SW35, which promotes power play. There's less of a draw for doubles players to use such power rackets though, as you usually sacrifice some speed. These days singles players tend to favour head heavy stiff rackets.