* TIFF images are frequently restricted by the TIFF class (Class F,
B, and NetFax) by which recipients. Rather than merely identifying
the archive as 'tiff' it seems feasible to be more specific.
* If you register a format name, then the name should be linked to a
well known, published, dated version of the specification of those
formats, and not to any possible future currently-unspecified even
if upwardly-compatible extension. That is, if you insist that the
format be called 'postscript', then it should be restricted to
'postscript' as known at the time of the definition of the standard.
Perhaps the situation with postscript is hopeless, but it isn't with
either 'rich text' or 'gif' or a number of 'audio' representations.
Part of the problem is that the very weakness of 'postscript' as an
interchange format is overly influencing your position. It may well be
that carousel will dominate postscript as a printable representation
exactly because Adobe finally is addressing some of the interchange
issues.