What I mean is that I'd love to see a scheme where ISPs only count any of your bandwidth that traverses their backbone. Or perhaps charged incrementally less per hop in the ISP architecture.

It seems like that would be neutral, simple, and sensible, though I'm not quite sure how peering and colocated caches would be treated. Probably the same as bandwidth for the end user since it's up to ISPs and content providers to do that.