All is not that easy
Apart from Orlowski and the large cable and mobile networks, no-one minds if SMTP traffic (all smtp traffic) gets lower priority than http for example.
As has been said many times, it isn't about the type of traffic you are managing its about management by source. Packet racism (if you like highly emotive analogies) where the management is based on where it comes from (or where its going) rather than the content.
Where we run into problems is when you have protocols which are source/destination specific or which compete directly with ISP-provided services. In HR it would be called, "indirect discrimination" and would include things such as setting a height requirement for employment so that south-east Asians would never qualify, or specifying only people with blonde or light-brown hair can will be accepted. The ISP equivalent is Facetime. You could say, "well, we treat all facetime packets equally" - they all get treated like torrents and SMTP - but that would be indirect discrimination because effectively you are victimising one particular group. What if someone starts using port 25 for voice traffic - do we then upgrade all SMTP to voice-level priorities? Never underestimate the ability of American lawyers to disregard common sense.
This is why we have well-known ports. Perhaps IANA will become so much more important than before. Do we make IANA the standard by which all traffic types are categorised? I don't really see a particularly better way. What happens to VPN traffic? Is that deprioritised? Does your voice traffic go horribly wrong because you want to protect it from snooping?
There may be no easy answers to all of the questions, but this we know for sure - no discrimination based on IP source/destination. If you mess with different protocols too much, you'll get things like Google's HTTP/UDP combined with chunked transfers to do even more obscured torrents. I'm sick of everything trying to run over http. just downgrade the stuff you don't doesn't matter that much, upgrade the stuff know does and stop pretending that streaming prevents piracy. Keep the consumers as the customer, keep a single published price list for data leaving the ISP network if data isn't being hosted there.