The idea of flying above the buildings would take a whole other level of code to enable a no-path style of travel. I don't think there are enough pay-to-play wizards to support that kind of addition. As it is, the set paths and streets are suffice to get from point A to point B and back again, with a small detour to point C.
Perhaps there can be an option to fly directly to the quest location (not free flight), but at least you can go up high and see the world below. Probably have to have a special mount, or even a pay-crowns-per-flight option.
Just more coding and time so that players can see their wizard flying in the sky. I love the idea of freedom, and maybe a certain PLACE where you can fly, but it'd take tons of coding and time for something practically useless.