Although old town scottsdale has desert landscaping, including cacti without thorns, and manages to provide shade using awnings and native trees, I don't think downtown Phoenix can incorporate it in its current state. I rather like the palm trees and would prefer more shade and some weather protection using awnings and native trees. It would be nice to avoid the sun and the rain.
God forbid you even suggest taking away the suicide lane on 7th street or 7th ave!