His defense is not that bad. Its quite pathetic that some people will immediately assume he's a bad defender based purely on last nights effort.
His opposite 5/8, Trent Barrett, was actually far worse in defense last night. He fell off two tackles that led to tries. Atleast Benji's mistakes were to do with being placed on the wing and not taking grubbers or being outjumped by Gasnier.
Bottom line is, anyone who doesnt rate Benji is either jealous or doesnt know anything about the game. He's a superstar already and arguably the best 5/8in the game.