Features I want in order to be able to draw in pure CSS. I've been using things like border radius, box-shadow, and lots of multiple backgrounds, including gradients, sometimes with multiple sizes.

Also, having recently discovered SASS, I want not only to be able to export the style as SCSS, but also go ahead and use concepts from SASS in the UI (e.g. define variables for things like colors, have lists, use mixins the way you would apply a filter in Photoshop)