Earlier: "...it would help to use syntax coloring (when in edit mode) to make the [wikimarkup] tags, and what's contained in them be another color..."
Doh - so simple!
I vote for this ... until we have a true, backward compatible IPE-WYSIWYG = In Place Editing, not in a subsequent window, What You See Is What You Get, in other words, click and start editing IN PLACE anything you see on a wiki page.
The color idea is probably still not section 508 compliant (see http://www.section508.gov/index.cfm?FuseAction=content&ID=12 and so on), but it would be a super simple aid to novice - and well practices - editors, nonetheless!