Link and Create Use Different Conventions for Space
There's a gotcha in the current Wiki design: if the user has a space in the link text, like this example, and then copies and pastes the link text into the page name in the create page dialog, the link does not work. The link is automatically translated to "this_example", and the page name remains untranslated as "this example". While the explanation is easily documented, it is contrary to reasonable expectations.
Recovering from this problem is also difficult, as there's no obvious way to rename a page.
One possible solution would be to do the same translation on page names as is done on link text.