The motor is in the hub, so I do not really see a problem. You might argue that the frame needs to be stiffer or stronger in some fashion, but that is a design choice a manufacturer makes. Stiffer is not necessarily better. Stronger is somewhat academic; steel is more than up to the task of added weight or stress. I do not think there is some other special engineering that needs to take place to make it a proper e-bike, other than the engineering that went into the motor system itself. The only issue is that because it does not have a sexy looking integrated battery, it is somehow "less" of an e-bike, which it isn't, really.