Some things I would like to see are pedal controlled devices. Something like a pedal controlled wheelchair, not powered by the pedals just control the forward and back motion. My mother with sever arthritis can still pedal but has a very hard time walking. It would be a little exercise doing something that needs to be done (getting around). A pedal controlled remote control lawnmower would be nifty also.

Needs "2011" in the title. For example the section about friction drive hasn't been true for about a decade now

You could attach pedals directly to motor axle and control charging power drawn precisely to ensure smooth rotation in absence of the flywheel. It could be really small.