Maybe you should add a few TIE bombers to the scenes with the imperial fleets. The only times we actually see those are when they are bombing the asteroids. Adding a few other ships (such as the TIE interceptor) would be great, too!
Another idea could maybe be a few TIE bombers over Cloud City, ready to drop 'em at any time. :P I got this idea from a youtube video, in which a fleet of TIE bombers destroy the rebel base (actually another Cloud City in the video :P)