More appealing if the back half rolled easily.

While we are at it, it would even better if it came with a bike mounted luggage system that converted to a front half carrying backpack.

Even more lovely would be the option to fold or separate. I'd settle for longer separation time (say two minutes) if folding were also an option.

Separable with a 2 speed kick shift coaster brake should be doable with a quick separation time.