I would like the developer to have the choice of what percent Apple gets (e.g. slider from 10% -> 30%) and that also determines the level of support (and discoverability on the App store?) that Apple gives. Would that type of system work?
There are lots of questions around compensation equality (i.e. the big companies get richer, the poor get charged more) but something besides the blanket 30% rule based on some metric sounds feasible to me