User blog comment:Brandon Rhea/Wiki Modernization Stage Two: Page and Article Headers/@comment-4968017-20170401105443/@comment-26402117-20170409123152

The big difference between the old header and the new header in terms of customisation is proper support for header background images. SU already has a high-contrast wiki header background and would probably do better with this new nav for that reason.

Here's a mockup of the new design in SU. Looks good to me.

This nav is much more easy to customize with CSS for me, so I imagine wikis will work less harder to gain a more advanced and attractive look. There is also the way it doesn't overly emphasise Fandom's own features but leaves them prominent.