small dia wheels do not deal with potholes well.

rolls instead of being carried like strida.com

anti theft devices. pitlock type skewers

generator hub

drum brakes like strida.com

low maintenance hubs: Phil wood, internally geared.

alternative to folding
sandsmachine.com

Chains stain clothing
condsider a belt drive: strida.com
shaft drive
enclosed chain
wax instead of oil