many great thoughts have already been laid out here - forgive me if I'm repeating one as I didn't read the entire thread.
I believe my best work in the urban environment have been made using imperfect subject matter.... it's careful use/placement of those imperfections that can really bring a photograph to life in my opinion. Maybe you should focus on photographing imperfections themselves for a time?
One other thought that might help... I rarely, almost never, think about waiting out light for a certain subject matter. I approach it from a different perspective. It's always the perfect light to photograph something... so go out looking for the light - not the subject. I find I discover lovely things I'd never consider as subject matter when I let the light itself be my guide.
Hope this helps in some way.
All the best.