i think janus has it right on the head. ALL of Gaara's techniques have been about manipulating sand, which has been implied to be a special trait he recieved because he had the Ichibi Bijuu sealed inside of him. With the bijuu gone, I doubt he'll be able to manipulate sand any more (especially not the high-speed sand or the instant defense that were particularly powerful).

Face it, Gaara without the Bijuu powers probably couldn't beat a decent Genin. We'll see if he retains some sand manipulation abilities, but if not, he's certainly one of the weakest Naruto characters now...