In my opinion this would be the right way to go: Keep up net neutrality and charge the user according to he bandwith.
What have we today? Flatrates everywhere that do not cover costs and ISPs trying to get additional money from companies.
Would you rather prefer it the other way? The user gets a cheap flatrate, the big companies pay for preferential treatment and if you start a video service your users can only download in 56k speed because you can't afford the ISP internet toll?
Problem only is the ISPs will try to milk both cows, the users and the content providers.