Maybe it's due to the fact that I have only had 2 hours of sleep in the past 24 hours, but I fail to see why anyone would use FireWire as a network interface other than TDM. I don't think people are concerned about their camcorders becoming self aware and hacking into their Macs via their FireWire connection.
What as network to do with it? If someone can access the firewire port they have root access to the computer. If you don't care about security that your problem. I dont think it's a big issue since it requires access to the machine. But still its a bad design feature of firewire that USB dont have.