As of now cities look to much planned. I would like to see them much more natural akin to medieval european cities.
a couple of suggestions to achieve this:
-randomly rotate buildings
-buildings of the same type should merge when placed next to each other (specially huts and farms)
-place road/dirt between different buildingtypes to imitate roads
-walls/hedges should stay even if you construct more buildings or delete old ones (however if you build a new fortress the whole current city becomes enveloped with walls as usual)