Optional is useful in a requirements RFC.
Feature x is REQUIRED
Feature y is OPTIONAL
I think it's clear from the discussion that we do not have consensus
on deprecating the adjectives and are not likely to, so I will remove
those in the next update. That makes me inclined to remove the whole
section and, as John suggests, keep this purely to the issue of
capitals... unless there's a real interest in deprecating "SHALL" and
"SHALL NOT", as they add nothing to the "MUST"s other than
history/custom.
Barry