I think the only option to the old tehnology, yet the fab design and ride quality is to upgrade the front wheel to a modern 12 inch 250W, lithium battery (give 1000 charges! as opposed to 300 of the lead acid, maybe lighter as well?)
(unless we lobby for a bit more power, given that it will extend the usability of it and save the carbon footprint)
Then we get the latest more reliable elelctronics and the keep the C5 image.
The C5 existing motor can be left and used as a generator with a suitable regulator, eother charging the 12v battery or the lithium battery.
The apprach would make the C5 more realible and usable, with extra power from gov, go anywhere! Just need weatherproofing, heater, carpets, wipers, sat nav...