The reason why I can't have quick sign ups on the homepage is because we need captcha (to prevent spam). For about 15 days this website did not have captcha implemented, and we were getting about 30 sign ups per day (where regularly we get around 3-8). Captcha on the homepage would look ugly.
As far as the smoke and violin, I personally think that's a beautiful picture, and the smoke softens the site a little. If the majority disagrees, changing the header really is the least of our concerns and should be no problem at all. The the main concern is getting the overall design faster, and easier on the eyes, with a better integration.