Your argument isn't stacking up. City centre sites are the ones with the best access to public transport, local services etc etc so they get the biggest dispensations for parking. Sites further out have less access to all of these things and therefore require more parking. So all of this already accords with what you want.
What you dont like is that these schemes dont have 1.5 car spaces for every unit, but they can't have because they simply dont fit unless the density is reduced, and if the density is reduced prices climb and availability drops.. but you get parking spaces
Heres a simple visualisation - your typical 70/80s semi D was 2 storey and about 8m wide, so it fit 2 cars in front of it if you took away a chunk of the garden. A typical semi D now is 3 storey unit 5m wide. This is exactly 2 car spaces wide in a lines on the tarmac shopping centre sense, but doesn't allow any room for a path to the front door, bins, bike storage, and some planting for privacy/biodiversity etc, so in reality they fit 1 car in front. Where are you even putting all of these additional cars? To satisfy your need we must go back to wider units = less houses, is that what you are looking for?
