Only the POST method allows for an entity body in the request. You can mix "GET"-style parameters with POST data in a POST request, but not vice-versa.
Though your post does brings up a good point regarding the usability of URL's. All of this extra cruft in the URL parameter list is really generally unnecessary. I would personally love to see more usable URL's of the form:
http://perlmonks.org/node/an.idea.for.hiding or
http://perlmonks.org/node/Re:%20an%20idea%20for%20hiding or
http://perlmonks.org/node/1234 as you suggest
The rest of the junk we see in the URL can
generally be obtained through more reliable (and less obvious) means.