oak theme: transparent gradient on "show more"
mark links to images when images are not rendered
clear space around form fields
shift panel/header on narrow screens with sidebar
filter images: mark links to files only
float message delete links to the right
Slightly wider main menu icon area, so custom link icon doesn't overflow in Firefox 29.
Larger padding in post excerpt heading, to match padding of post excerpt body.
Slight increase in default line height. (line spacing)
Apply padding consistently on post excerpt components.
Set padding for narrow screens, too.
Inner shadow on textareas and text input boxen.
Don't allow Chromium (and other browsers) to highlight the currently focused input with some arbitrary colour that may not match the current Libertree theme.

This should be the responsibility of each theme to style for themselves.