With the introduction of the new uni-body Macbook it's a step forward for Apple. Some think that it's also a step back. For years, Apple has offered (for the most part) Firewire 400 on it's notebooks. With Firewire you could connect an external hard drive, scanner, video camera, and other devices to your Mac. Overall, it provided better use of throughput and performance compared to USB 2.0.
Sure, it will be missed, but let's not dwell on it. Firewire still lives on with MacBook Pro, iMac, Mac Mini, and Mac Pro. You may need an adapter from Firewire 800 -> 400 to support your legacy 400 devices, but if you need it, it's less than $20.
Apple is probably just getting ready for the next level of technology. Without deprecation of old technologies, there leaves no room or incentive for advancement.