I once have a PhD friend working about urban planning in a university in Hawaii, would definitely ask him about this. If I can get anything useful, I will post it back here for you. My personal thought is that: everything needs planning, and especially urban planning is a wide range of multi-disciplinary field, that would help you to fulfill part of your dreams, but not totally since dont expect too much that you can change everything. Sometimes, your thoughts and ideas might be good, but whatever good if they are not to be applied in the real world. Dont want to spoil your ambition, just a small reminder.