if this can be made lo-tech, without any software and hi-tech gadgetry, then it's a killer.. even if 10-20% less efficient. Most people don't need racing.. It won't need any gears and switching them anymore, as electrical motors have mostly same torque on whole range ; The force of pushing pedals does not need to match the uphill - as long there's something in battery ; And one can keep pushing downhill regardless of speed, and that energy will not be wasted..