True, the Midway is pretty big compared to the battleships, but so is the Excelsior and it's only a BCH. I didn't change the size compared to the stock version so I can only assume that was the original intent. Most stock ships aren't perfectly scaled but they aren't too far off either. Of course, the Midway isn't intended to be a stand-alone combat ship, it's more of a giant shuttlebay.
Yeah, the Missouri even dwarfs the Galaxy class and the Yamato is even bigger than that. The Sword of Khaless is only 686 meters, and not as heavily armed. Obviously, the KA guys had a bit of an inferiority complex.