I think you're forgetting the true power of the transformer. It's not that they have a powerful ship. It's the ability of Teltran-1 to scan the area and alter the transformations of the autobots to blend with the local populace. Your autobots would then be able to turn into Tie-Fighters, Landspeeders and other forms of awesomeness. They can slip right into the middle of an enemy city using a holographic driver or with some crew of one of the other vessels and to perform espionage or sabotage.