The path from a neutral Internet to the one Comcast execs dream of at night is a slippery slope. Even embracing partial steps towards that end will lead to yet more, as the specific cases are generalized down to something so vague and weak that any ISP can use it to assign whatever priorities they want to whatever traffic. It will go from "user controlled fast lanes" to "dynamic fast lanes" to "ISP curated fast lanes" to "ISP controlled fast lanes for the sake of general network health".
No one will care that their netflix packets are prioritized lower than their voice packets, since netflix streams and voice needs to be near real-time.
Latency and throughput are very different things. NetFlix does not need to be "real-time" -- it only requires enough throughput to build up a buffer big enough to smoothly play content and handle network variations. Voice calls are very different. They require very low latency and cannot be buffered.
No application bandwidth limiting, just prioritization.
I agree, but we already have that and you even named it. Quality of Service and Class of Service have already largely solved this problem. The only people saying that this kind of prioritization is the same thing as provider or application level throttling (fast and slow lanes), or that QoS will be illegal under Net Neutrality laws are the big telecos and their paid shills.
Once you open the door to "fast lanes" even a little bit, that's it. The level of neutrality will fall over time until it's another fondly distant Internet memory -- kind of like anonymity and the Fourth Amendment.