"Parking garages are much superior to flat parking lots, especially if you put them underground, underneath the buildings in question. Keep the eyesores hidden."
Indeed. A lot of this sort of infrastructure can and should be built below-ground. Parking garages, warehouses/storage, utilities, the works.
"Going further, it would be beneficial to abolish megastores and return to more human-sized retail outlets."
Not sure if I follow. Megastores are nice as one-stop shops, reducing the need to drive around town to get everything.
I am in favor of making them more modularized/sectionalized, such that they can be rearranged vertically (whether above-ground or below-ground) and reduce the horizontal footprint. Their similarly-sprawling parking lots also can and should be replaced with underground parking garages.