While I completely agree with the function of what you suggest, the opinion you states dependa on the definition of "good design".
We told other members here what we would have to sacrifice and they chose a non-removable battery.
I tend to think myself as a halfway design/function guy and I do think we would have needed to make a lot of sacrifices to the design to make the battery removable. However the most limiting factor is that since we are a small player, we could not afford to design a custom battery.
However if we ever do have such an option available, we'll make it happen