I'm all for this, with the option of turning it off. I hope some of the crusty old-school devs keep an open mind about it and don't try to shut it down before it can even get a foothold. With the speed of today's machines and the advances of tomorrow's, speed should not be as much of an issue as many fear. And Apple is not stupid, I'm sure they're thinking about many of the things that are being mentioned such as circular reference handling.