The IETF has done it's job with 6to4, but like you said we can't force
people to deploy it. But let's stop and think about 6to4. Aren't some of
the same "tricks" or ALG's that are planned to make applications work
with IPv4 NAT, applicable to 6to4? If so, then we must find solutions
now since 6to4 could be with us for many years.
Given that the whole point of 6to4 is to allow IPv6 packets to be
passed end-to-end without modification, I don't see how ALGs apply at
all. NAT-PT of course has similar issues to v4 NAT, but NAT-PT and
6to4 are different things.
Keith