I'd say this is an improvement on the old design. Though not as pretty, it's more durable and lighter. Shattering the glass is a common and expensive problem for customers. It's nice to have one less fragile item on this expensive device.
More to the point, Apple tends to go for simple design and ignores fashion trends. They have the colored iPods but that's more to appeal to kids and people that want a little more personalization rather than because yellow and green are in.
Also, I'm going to slap the next pundit that refers to this as "scuffgate". Protip, guys: Watergate was a proper noun, not a random mashing-together of words.
Its not designed obsolescence, but rather a triggering with our general Western inclination to eschew any flaws in what is usually an extremely personal, desired object: the bar of soap.
The more our gadgets progress towards 'soap' in terms of physical usability, the more this factor comes into the design. Slight dings in perfect surfaces beget more dings, until eventually the device requires replacement..