User blog comment:Brandon Rhea/Wiki Modernization Stage Two: Page and Article Headers/@comment-4004899-20170404194226/@comment-5558012-20170404195612

Fluid width. Wikia has already been there where every screen size experienced articles differently. Makes formatting articles more difficult/annoying. We now have breakpoints that work much better and I'd hate to see a fluid width of the article area return.

The global nav isn't going to have another variant because Fandom require consistency.