Also, changes in implementations have been known to contain bugs, hence by forcing the changes to be to cl:case, we are going to potentially affect existing code bases, for no discernible gain.
That's why regression tests exist...
Which brings me to another question I've been meaning to bring up w.r.t. the latest CDRs: Would it be sensible to have a defined package for these kinds of smallish extensions (like e.g. the index types, as well), maybe cdr-cl or ext-cl, or whatever? Has this been discussed already?
Sounds sensible to me, yes.
Leslie