I'm not sure what you mean by routing above. Are you suggesting there's
some negative externality in that NAT makes the routing infrastructure
more complicated? If so, what is it?
If you're multihomed and your route changes, your address
changes. (Yes, this happens).
I am profoundly weirded out by reading an IAB member argue
that something that's got broad market acceptance is
tautologically okay. I agree that there's a real problem
here that NAT is trying to solve, but I certainly wouldn't
treat it as a given that NAT is the best, or even a good,
solution.
Melinda