I think that is the best approach for most economies where used car market is doing well.
pair a 30kwh or ideall 40kwh battery with a small removable generator that can charge the car whilst driving to enable long distance journeys where a charging point may not necessarily be available.
I the BMW i3 route maybe a good start then develop a dedicated portable generator – I believe the market for that would be huge and give customer flexibility in their energy source.
The nissan epower route is also one to investigate – frankly shocking that all the vehicle manufacturers havent gone down this route already to enable them to start being competitve.
I think cars are a power station (just like your house is a power station once you add solar panels and or batteries to it) that could be made infinitely more useful if cars can load and discharge electricity whereever its needed. even charge other cars as 12kw – this should be a standard that they should be forced to adopt. Once that is in place energy prices in most countries will be brought down and subsidies no longer required – the other bonus is that anyone can now make money from what is likely thier second biggest investment during their lifetime.