I think the next major adjustment would be to add Atlanta/Florida and DC/Baltimore/Philadelphia. There are already some "other east coast", but I think this will stay on the front page long enough to get many more votes than it has now, so the mixup will become smaller as votes come in.

Edit: I'd also make Michigan into "Michigan/Ohio/Pittsburgh", add "Mountain States (Arizona/Utah/Colorado/NM/ID)", and add Other Midwest, and Other South. Then I'd leave it alone. :)