If you remember, Imperial City was enormous compared to the cities in Skyrim. As I think back to it, I would often get lost in Imperial City. I guess Imperial City was about the size 2-3 large towns. Whiterun's populated exterior, like other Skyrim towns, is about as large as it's interior, but much less populated. Shouldn't be that hard turning it into really looking like Skyrim's version of the Imperial City. Something like a land based harbor, with wagons instead of ships.