I agree with the author's central point, although I don't know if I would de-emphasize the importance of the visual designer to such an extent. I think a couple of the examples he links to (Google, Facebook) are outliers. They succeeded in spite of their lack of visual design because their products weren't just executed well; they were executed extremely well. Generally speaking though it takes a bit more finesse in order to make your users feel at home using your product.

With that said, I agree that if the core product isn't well engineered then no amount of lipstick on the pig is going to make it usable. You can paint rust any color you like but it's still rust.