Come to think of it, I'm sure London will be the best city in the series. Places like Westminster, Buckingham Palace, Tower Bridge, St Pauls Cathedral, The Royal Albert Hall, the Tower of London, as well as countless more huge museums, colleges, galleries, cathedrals, and other buildings. It will of course be a condensed down version of London (these places are too far apart in real life), but nevertheless, it should be fantastic if they can pull it off, unlike Unity. It is also the first location they've ever done where they have photographic visual references, which I'm sure will make it even more authentic.
You have to understand that London by that point had been the capital city of nearly half the world for 200 years, the spectacular amount of wealth flowing through meant that huge, exquisite structures and monuments sprung up almost weekly throughout the 19th century. 18th century Paris didn't have anything on Victorian London, in terms of architectural achievements.