Lucas,
Personally, I think starting on a basis of ignoring QUIC transport's core method of exchanging application data is a bad idea.
I'm not suggesting that. I suggest that we first agree on the basic multipath mechanisms without taking too much time to discuss different and diverging application requirements. These mechanisms obviously need to take into account the core characteristics of QUIC. One example is that in contrast with MPTCP, MPQUIC acknowledgements do not necessarily need to be transmitted over the same "path" as the data that they acknowledge. This gives more freedom to an MPQUIC implementation than an MPTCP one. Another example are the flow control frames. Once we agree on these application-independent mechanisms, then we can start to discuss about policies and how to handle them.
Olivier
