* Browsing: I don't like the blue background of "Browse topics" when the ToC is open. This looks like a button (actually, it doesn't, but in the same way as buttons on newer parts of the mediawiki UI or on facebook don't, so one might think it's a button). The function of that area is somewhat comparable to that of a 2-state button, but those shouldn't be labeled with a verb that only makes sense in one of the states.
* Marking topics with recent activity: the color we're familiar with in this context (from e.g. history pages) is green, not blue.