While it is obvious that we have no time to redesign IPv6 for the set of
valid reasons you mentioned one could observe that we do have time to
deploy it wisely via ID/LOC split architecture model.
Dual stack networks and all networking gear stays intact and depending
on the choice of ID/LOC split solution some hosts may require a patch.
I believe some/most of problems from the quoted article and repeated in
this thread would get solved with such model.
Perhaps it's time to build LISP to ILNP inter-working and roll.
v6 is not the protocol I would have chosen. For that matter, it's not the
protocol I pushed for, as hard as I could, in the IPng directorate. At this
point -- with all of its technical mistakes, IETF omissions, and difficulty
of converting, we're stuck with it; we simply do not have time -- even if
we agreed now on what we should have done, way back when -- to start over.
Do the arithmetic... Assume we know, today, the basic structure of a
perfect replacement for v4. It would take a minimum of 3 years to get
through the IETF, not because of process but because there are so many
things that it touches, like the DNS, BGP, OSPF, and more. There are
also all of the little side-pieces, like the ARP/ND replacement, the PPP
goo, etc. After that, it's 3 years of design/code/test by Microsoft,
Apple, Cisco, Juniper, et al., following which we have the whole education
cycle, the replacement cycle while old boxes die off and are replaced, and
more. (Look at how many Windows XP boxes still exist -- and we're well
into the second major release of Windows since then, and Windows 8 might
be out before the end of the year.) By my arithmetic, it's a dozen years
minimum,*after* we've agreed on the basic design.