Networking change causes distribution headaches

If you really mean 1 Gigabyte/second transfer rates, that means a 10G Ethernet link or the equivalent using SONET/DWDM, from a single host, and probably over a long fat pipe (e.g. satellite), which sounds exceedingly unlikely for Ubuntu, which is aimed at consumer and business usage - more like something CERN would do.

IMHO, anyone who is not running Ubuntu on a supercomputer using that type of network connection can safely ignore the chance of the PAWS issue corrupting their data.

Even if you meant 1 Gbps, that's an impressive sustained rate for a high latency network session (i.e. the ones where sequence numbers matter, hence over a WAN). A Gigabit Ethernet LAN would almost by definition have low latencies (a few milliseconds).

I'm generalising here, but I really think the PAWS issue is irrelevant to people who are likely to use Ubuntu. If it was an HPC distro it would be quite different.