About the video i/o: I think is not such bad idea but... there are usb devices that can do that, some are cheap, some otheres not that cheap. For $700 you can get a Firewire interface with analog audio i/o, S-VHS i/o, composite video i/o, plus a firewire connector.
If Apple uses a S-VHS video out put it will create some disconfort in the market. Beside, not everybody uses video editing software, and if you do you may get a better interface, more popular than S-VHS. Or you can burn the movie in a DVD, that is what is for. Apple is pointing that direction.
About audio i/o: Apple needs the audio imput back again. The audio imput was avalible until the G4 450 came out. I have a G4 400 and I'm very glad it has it.
There are some other usb interfaces for audio only. May be Apple was realising that not meny people was using their microphones as well in the early days the Macs came with and entire OS manual but it doesn't any more.
I think the audio imput is very nesesary, even with not microphone. May be there was some kind of deal between othe manofatures.
Digidesing came out with a very nice interface that cost $700 again, is USB compatible and comes with XLR i/o, spdf i/o and rca type i/o. That is very good, is the sucessor of the Audio Media 3 card.