Not traffic imbalances at peering points. Rather a situation where data has to travel further, through more nodes from source to destination. Shouldn't a logical system allllow that data to cost more? Or for example through the same number of nodes but more expensive source nodes.

Beyond that, there is some "discrimination" I would be just fine with. For example why should the end consumer pay the cost of YouTube ad data?

The fear is of course discrimination on political or ideological grounds, not just economic. but it would be fairly obvious and nearly impossible technically for an isp to pull that off. And a net neutrality regulation or even ownership at the state or local level would be perfect. You only need net neutrality at the end points where there is no competition, not in the network at large