I'm starting to wonder who was put in charge of determining which soul society characters came to earth during the filler arc. Did they look at the manga, decide that all the cool characters were taken, and start purposefully bringing lame and useless people?
Ganju isn't really that bad though. He's not really that weak either though. He my have only taken down a seated shinigami through luck and tricks, but he fought half the normal 11th squad members and won, so he can't be that pathetic.