UI is fashion-driven like clothing or furniture or car design. That's not new, it's just hard to admit for us techies that such a thing exists in our world. And just like with fashion, some changes are not for 'better' but for 'cooler' or 'more interesting'. The question is how far on the 'worse' scale you're willing to go to get up on the 'cool' scale. Otherwise, we'd all still be running Windows Server 2000...