No. The wiki index is a special node, you can't actually change the kind of node that it is.
However, you can change the Wiki link in the navbar if you really want to, by creating an event listener at vw_nav_links.
What might be useful instead is a sideblock that lists pages in a specific area. Since you can set sideblocks for the index only, this might achieve what you're looking for.
You can do something like this with the WIDGET BB-Code: