I think that a future Common Lisp could profitably default to lower-case instead of upper-case, and unify argument order. It probably shouldn't default to gene

I think that a future Common Lisp could profitably default to lower-case instead of upper-case, and unify argument order. It probably shouldn't default to generic functions due to the performance implications. It could more-fully specify pathnames for current platforms. It could specify something like Go's channels & goroutines. None of that's probably worth the bother of a new spec. CL21 was, as you note, an interesting experiment, but I wouldn't run with it.