Thanks for looking into this, Alfred. It's definitely needed.
Also, I find that it helps to provide examples of acceptable values in the description, and I think we should recommend that people do that.
I just wanted to point to this orthogonal but related piece:
http://www.collaboraid.biz/developer/config-spec
which would further help administrators by providing more rich form-builder based forms for editing package parameters and other similar things, complete with drop-downs, check boxes, radio buttons, and validation, as appropriate.
No implementation has started yet, but if time and funding permits, I hope to sneak it in to 5.0 or 5.1.
/Lars
