Since this probably is the wrong place for this discussion, I'll simply
point out that every supposed advantage you give for CMR could equally
apply to a properly designed key escrow system. Both provide access to
data for those who have access to the recovery keys, and any system
controlling access to CMR recovery keys could be used to control access
to escrowed keys.
The only advantage that PGP Inc have suggested for CMR over key escrow is
that you can write your own version of PGP which puts garbage in the
CMR key field. At the same time, it builds a 'feature' into every copy
of PGP which could at some point in the future be used to provide
government access to messages by forcing users to encrypt to a government
key. This, to Adam and others (including me), is so great a risk that
we'd much prefer key escrow or an alternate system. In fact, key
escrow does not have to be built into PGP at all; it can be implemented
by an external secret-sharing program.
I for one do not want to see any such system included in the Open PGP
spec, but strongly suspect that PGP Inc will push it, since CMR cannot
work properly unless every implementation of PGP supports it.
Mark