Most of the college kids I hang out with seem to prefer Taco Bell; they have a nice $1 menu with great value. Nice thing about McD is that you know pretty much what you're going to get. I tend to eat there while traveling. I suppose if there were more Taco Times I'd go there instead.
As far as the nutrition goes, when I worked heavy construction we all ate at McDs and ordered huge meals with fries, a shake and the largest high fructose corn syrup sweetened drink they'd give us. We refilled the drinks on the way out. And all of us had a hell of a lot more muscle than fat. The reason people are so fat nowadays is that they live lives of leisure while eating the diet of a working man.
But all in, I think the original poster is right. MCD is doomed. The problem is that the fast food market has fragmented too much. You can make good money as a boutique hamburger chain, or a pizza chain, or by specializing in mexican-american food, etc., but the market MCD sells into has been fragmented. And there's really no solution to that except specializing themselves. The only solution I can see is pushing towards a boutique hamburger chain. To do that, they'd keep most of their standard burgers and add some selections stolen from a recently very successful hamburger IPO. But then the question is one of marketing. MCD markets to children which is somewhat incompatible with fancy burgers. And as far as marketing to children, the number of children seem to be in decline and that market is probably saturated already. So I do see them as having a rough go the next 10 years, and I can imagine them going away. Right there with other companies, much older, that in my youth no one thought would ever fail.