I think expectations of battery life beyond a day with technology at its current stage is unreasonable. battery in the strap? really, think how think the strap would become, be realistic.
Charging it each night I don't see a problem with. I do that with my phone already, and I take my watch off each night too and place it beside the phone ... so its hardly a great chore to place it on a magsafe style charger beside the phone.
In fact, the clever solution should have been to have the iPhone use a similar charging method, so you can place them both beside each other.