Formula E sounds like an interesting premise but two car swaps per 1 hour race? An electric sports car series would make more sense

Having the drivers come in and change cars twice per hour as a means of dealing with the fact that current battery technology has terrible energy density doesn't seem like a great solution. 

However, swapping the batteries is also less than ideal.  In addition to the obvious cost considerations, there is a significant safety reason behind why Project Better Place and +Tesla Motors have both proposed completely automated battery swap systems. Handling large high-voltage batteries is cumbersome and dangerous.  

Perhaps a better solution for Formula E would have been to incorporate a larger battery and something akin to Tesla's high-power supercharger system.  Better still, don't do open-wheel cars where the size of the battery pack is so inherently limited by packaging constraints. Do a full-body sports car.  

How about something like a modern battery-powered Can-Am series? 

Create a car the size of a +McLaren M20 or +Porsche 917-30 with sufficient battery to run a 45 minute sprint race.  Then do two or even three heats in the course of a day with time to recharge between heats. That could make for some interesting racing.?