For what it's worth, I consider everything exported and documented in the QL-DIST package to be fair game for direct use. No need to do print-object scraping on the results of ql:system-list, you could use e.g. (mapcar #'ql-dist:name (ql-dist:provided-systems "quicklisp")) instead.
I know this will never change, but I really wish people would stop using lisp as a synonym for common lisp. CL is not the only lisp.
The confusion over the term "lisp" goes both ways, i have spent an infinite amount of time explaining to people that common lisp is not the small subset of a subset of scheme your CS professor tortured you with.