The cities in skyrim are patetics, the capital doesn t even have 100 souls counting rats and rockroaches as denizens. Its as bad as Oblivion, and even worse than Morrowind.
Solitude is bigger than Ebonheart. And Windhelm is larger than Balmora. Whiterun is much larger than Ald'Ruhn, when you take the surrounding farmland into account.
People are GREATLY understating the size of the cities. No, they
aren't smaller than individual cities.
The populations are smaller, yes, as are the number of buildings. However, in Morrowind, buildings were less than half the size they are in later games. Furthermore, Morrowind's cities were more heavily populated than Oblivion and Skyrim's because the lack of NPC schedules required a NEW NPC to be used everywhere you'd expect to find someone.