I believe that our current standards in the Code are more than adequate. Of course, there is nothing wrong with over-wiring, but most of the time it is not necesary.
And of course, there are other factors to consider. Copper is pretty cheap right now. What if the price of it goes up? Then you may have to rethink installing #12 on everything and using extra circuits. And dont count on the cost of electricity staying low forever, either.
Hopefully, lighting and appliances will become more enery efficient in the next 10-20 years. That will reduce the need for extra wiring too.
