User blog comment:Sannse/Sneak Peek at the New Look - Themes/@comment-3100721-20100921041200/@comment-8-20100924003810

I'm confused here... yes, only admins will be able to set the theme for a wiki - but that's just as it's always been.

The change is that you will only see the default theme, rather than be able to over-ride it with one of the standard themes. But you will still be able to modify that default for yourself via your CSS pages