The Theme tab has been cleaned up some as there is now one script to edit the four stylesheets. It's also been improved to be a bit easier during multiple edits.
Also, the custom sidebar content is now available via the theme tab, which it always should have been. I'm also planning to expand it to have at least two and probably 4 custom sections, to accomodate the current trend towards having advertising on both sides (right now, to put advertising on both sides you have to stick it into the sidebar templates directly, which is not a big deal but is sub-optimal).