Library/MediaWiki/Improving MediaWiki Subpage Title Formatting
In short, the "improvement" here is to display only the subpage name and not the parent page names.
Improving Links to Subpages
A simple MediaWiki template can be used to display only the subpage name and not the parent page names within a page itself (i.e. the link). See Template:SUB.
Improving the Title on the Actual Subpage itself
Rather than displaying the page first header as "Rootpage/Subpage/Subpage name", the main header is changed to "Subpage name" only. The subpage links then include links to every part of the hierarchy.
This is accomplished via a simple JQuery function added before the "</body>" tag in Vector.php (assuming you use the Vector skin). This also assumes you have JQuery enabled on MediaWiki.