It would be nice to be able to customize things like widget headers ( background and color ), widget link colors, and widget hover colors. It would also be nice to differentiate between a navigational widget ( a widget that just outputs a list of links ) and a content widget ( Text, HTML, Image, etc. ). Doing so will allow you to have generic link styles for content links and navigational styles for listed links. For example, a list of categories isn't a nav menu necessarily but in a sidebar it's more for navigation. This could be achieved via `dynamic_sidebar_params` filter hook. In any case, more sidebar/widget style options would be neat.