I actually liked the look of Kirkwall, although I preferred the worn and dilapidated look of Lowtown to the ostentatious grandeur of Hightown. Isabela was completely right when she said that Hightown might look (and smell) prettier, but was completely boring and drab in comparison.
I wouldn't mind seeing some Kirkwall-esque graffiti on the walls of Skyhold either, particularly in Varric's quarters. I always pictured him as being the individual responsible for drawing the illustrations in his room in the Hanged Man, the Kirkwall map and the portraits of the companions in Cass' Big Book of Everything.
Does anyone know if the decoration affects the entire Keep or just certain main areas?