Sites like craigslist are in fact well designed, it's just that those sites feature a very minimal design (less = more). In fact if you want an example of a site that veered to encourage bad design MySpace is a good example. But even there you could argue that it was a well designed site because the audience for that site wanted their pages to be ugly and hard to read.

I think you'll find that really good design (and designers) always think of their audience first. This isn't just a design mindset, but a marketing one. That thinking is essential to creating any good product from a website to a cooking wok.