It seems to me that the first thing they should do is up the voltage of ordinary gasoline cars. Instead of a 12 volt system, they should change over to a 36 or even a 60 volt system. Sure the batteries will be bigger and more expensive, but they will save on wire and motors. A sixty volt motor is much smaller for equivalent power output than a 12 volt motor. Wires can be much smaller diameter too because you need fewer amps when using higher voltages. IN a luxury car, the weight savings could be quite a bit.
Now, the battery will be much larger and heavier, so there will be more incentive to find lighter smaller battery technology.
This electric vehicle development needs to be done in very small increments. I remember reading that they are going to improve the electrical systems of semis so that they don’t have to sit idleing all night long in the winter. THat is a good first step. Now we need higher voltage systems in passenger cars.
I also remember reading that one of the semi engine producers(cummins I think), was offering an option that would shut down all non essential electricity consuming devices and also shut down the alternator when accelerating hard or climbing hills. THis gave the engine just a little bit of a power boost. Then on the down hill side, the alternator would power back up and recharge the battery. This needs to be applied to passenger cars too. It would be even more productive on gasoline ingines since a gasoline engine needs electrical spark to run.
THen once these electrical upgrades are perfected, try applying the technology to hybrid vehicles. And once hybrids are good enough to stand on their own feet without government incentives and subsidies, they can start shrinking the internal combustion portion of the hybrid and increasing the electric portion of the hybrid. Eventually, you will have an all-electric vehicle.
Electric cars or hybrids already use much higher voltage than 12 volts.
The Tesla uses a nominal 375V
http://www.teslamotors.com/display_data/TeslaRoadsterBatterySystem.pdf
The generation II Prius Hybrid uses a nominal 274V
http://www.cleangreencar.co.nz/page/prius-technical-info