The G-7 is, unfortunately, a victim of its own success. The most powerful force in its beginning was then-U.S. Treasury Secretary George Shultz, who believed that finance ministers and central bankers of different major economic powers needed to meet and get to know each other before there was a crisis, so that they would have already set the groundwork for cooperation when rapid cooperation turned out to be suddenly necessary. It seemed to work: the G-7 finance ministers got to know each other, business seemed to get done, and they told reporters that it was a useful meeting.
Then the prime ministers--most of whom are scared of their finance ministers--decided that they had to have a share in this positively-reported set of meetings too. They began to set up their own G-7 meetings. And then their policy, political, and media staffs began to come. And then the downward spiral in the usefulness of the meetings began. Because you can't have a big meeting without an important final communique, right?
Looks like to be informal in our times you should first create completely useless formal structure. With sole purpose of mixing right people without alarming the world. :)
Seriously - it is time they should start talking via the Internet... Will be a lot cheaper than all this BS with planes, cars, hotels, banners and so on...