Im not sure I would describe the redevelopment of Battersea, Nine Elms Lane, and the building of the new US Embassy there a 'few' residents. I believe the number of new homes is something like 35,000. However im also sure that with a tube station placed further up Nine Elms spurring from Vauxhall, the traffic in the area will be kept minimal.
On the story of the burying the south circ. As much as it would be a lovely idea to make it all just magically disappear, I dont think there is a logical and practical solution for it. The problem with having it ducking and rising constantly is the huge area of land needed for the slopes and rises, just not practical.
There is no real solution to the increasingly busy roads of London. Public transport is an option but capacity is struggling as it is. Now take 250,000 car journeys off the roads daily too.. OUCH!
Will be interesting to see what the future brings. But in the meantime I shall potter about in my little 2 seater micro car with its little engine and do my bit to minimise impact.