I'm disappointed it doesn't (seem to) do regenerative braking... so elegant, don't waste that power, reuse it! But I don't think this is a big selling point, and you can always add it later.

I think your marketing approach is what will make or break it: "non-sweaty to dates/interviews" and the phone-charger could be the killer app (perhaps look into what segment actually experiences this pain most? Many of today's phones have adequate battery life for some people's usage; target those phones + usages that don't).