I've upgraded the ikiwiki-nav plugin so that it now supports:

• Wikilink autocompletion through omnicompletion.
• Jump to previous/next wikilink.
• Open the file corresponding to the wikilink under the cursor in the current window/a new window/a new tab page.
• Create the file corresponing to the wikilink under the cursor in the current window/a new window/a new tab page .

You can download it from here