I think we (private flying pilots) will be the first to use battery powered airplanes regularly. Some are in the market already, and two seat planes with about 1 hour endurance are getting close to where a training aircraft needs to be. If performances were doubled to around 2 hours things start to get interesting for flight schools. Service and maintenance costs are very low, except for batteries but that is a quite predictable write-off with time.
Conversion to piston or turbine should not be more challenging than conversion between piston and turbine today. Regarding things like carb-heat, I was actually shocked to meet pilots at my current club that had never flown a plane with carb heat, only new 172SP's with injection engines, so there we have a challenge already today.