Id like to see a focus on improving clutches or additions of variatiors. for a modding stand point most moped clutch are too weak and from a stock rider stand point these bikes lack too much crucial low end power.
otherwise I think any improvements making the bike either safer (modern lighting, turn signals, etc) or more reliable. i hate to say this but... i love mopeds but I hardly ever recommend someone to use one for a commuter. there's just too much jank with these bikes which will leave many pushing it home. I like the CDI idea (a mini rotor cdi would make the bkke torquey and reliable). Fuel injection that actually changes your fuel air mixture ratio... could help people avoid seizing when the climate drops over night.
perhaps that's all a wish list but areas I would love to see addressed.