I wanted to throw out the idea of expanding the center blocks completely across the width of the page and expand over all three columns. Instead of being smushed between the outer columns, put the centerblocks above them.
I think my main reason is basically for cosmetics and appearance, but I think it'd be cool to be able to do. I think it would make things look less "squished" if the center blocks were above the columns and whatever you have set to show on the front page (articles, forum posts, single page, etc.) were set in between them.
An option to be able to switch between having them expanded and how they are now would be best.
I keep thinking of a newsbox and an HTML admin block the most, of what I'd like to see expanded like this.