User blog comment:Rupert Giles/Global Navigation January Update/@comment-4899461-20150202232851/@comment-24416108-20150203214603

"In addition, we are still aiming to have an improved global search that allows users to find any piece of content in the network from any page. Ideally this kid of experience makes everyone's community better by not having it so siloed from the rest of the site. But an actual global search is better understood with a consistent global element (think searching on Youtube, Facebook, Amazon, etc.)"

- Rupert Giles

Main difference between Wikia and Youtube, Facebook, Amazon etc, is that while those are sites that have one and the same subject(video's, social content...), while Wikia consists of many sites with complete different subjects. I'm an admin at my most active Wiki, but I don't even have an idea of how many other wiki's there are. They're completely different sites, with different styles, different admins and different subjects.

I understand the need of branding. However, you can just force the font and layout of the bar, while still giving admins the freedom of color, and you'll end up with many different bars that still feel the same.