Would you just be able to transport some torpedoes into the middle of each Imperial ship? Doesn't seem to have much in the way of shielding.
Star Wars has always been 'off' to me - you have the technology to build a Death Star, but asteroid fields are still a great hazard.
Also the overall technology of the Federation seem to be higher and that opens many doors into winning a conflict outside of straight weapon to weapon. For example - some sort of biogenic attack, hacking into Imperial computers and having them self-destruct, taking a cloaked ship up to a destroyer - wait for the shuttle bays to open - pop in a few nukes.