I'm a little torn on this. If skins evolve within Wikipedia (and foundation projects) but not on mediawiki core I won't feel like we're putting out a good product. That said I do think there is value in the default install skin on mediawiki differing from that of Wikipedia, it waters down the brand.
The problem with simultaneously maintaining development on the Wikipedia skin and a second "equally good but different" skin for distribution as her default skin for a mediawiki install is that it is a lot of overhead, certainly more than we can handle right now. The other question is how different do they have to be, a brand isn't just a logo and name it's the entire look and feel. Does mediawiki need their own?
It's a problem that I don't have a clear answer for just yet but something that we should think about.
Sent while mobile
Flagging this bug for the folks on this list:
"Make Wikipedia distinct by styling of a prominent UI feature differently than the default"
To be clear, I know about ongoing work to develop and implement visual identity guidelines. The bug above is related but much narrower in scope, referring specifically to a problem incurred as a side-effect of the popularity of MediaWiki as a platform.