the problem with using ASNs is that when you think over the projected lifetime of IPv6, there will be *lots* of ASNs. Note that the 4-byte ASN draft is entering the standards track in IETF. Don't think that tying PI to ASNs is anything more that passing the problem to the next generation (if that long... :-)
A policy that says "if you qualify for an AS number then you also qualify for one IPv6 /32 allocation" does not run into any problems with 16-bit AS numbers. That is because you still have to qualify for the AS number before you can get the address allocation. Of course, after 16-bit AS numbers come in, some people may wish to make it easier to get AS numbers and we would probably want to change the address allocation policy at the same time. If a policy works for 2 years, that is good enough. RIRs can change policies in a few months if there is a need.
It would seem obvious that as network connectivity becomes essential for doing business, it must be reliable. It is unwise to carry forward the IPv4 multi-homing model for network resilience with just faith that the system will be able to scale to an ever larger number of routes. IPv6 has so far failed to deliver on its original promise of seamless renumbering and multi-homing using multiple prefixes. The hard problems still need to be solved in a way that can scale for decades to come.
That leads to geotopological IPv6 addresses but that is another thread... --Michael Dillon