Re: Yes, that's one of the bad design decisions of USB
"Obviously the sane way to go would be to have dedicated ports again. Connect printers and scanners via Ethernet, connect input devices via some sort of overclocked PS/2, and have a special port for mass storage devices. That way you could essentially eliminate all harmful device spoofing..."
Not really. What's to stop an evil keyboard from presenting itself as TWO keyboards or simply transmitting stuff AS that keyboard. Same with mass storage; just present as TWO mass storage devices, one of which can perform auto-launching tricks (even with AutoRun turned off). Plus the reason these things have appeared is because uses have arisen for them, such as non-Ethernet laptops needing to hook up to a wired network or one with a single port needing to connect to two of them. Or someone needing extra desktop real estate but only has one video port.
Besides, do you REALLY want to go back to the jungle days of finicky PS/2 ports that require interrupts and can seize the system if you unplug them and so on? Remember SCSI terminator packs? The fat Centronics printer connections? Oh, and multi-function devices don't have a universal network communication standard, meaning you're usually locked into the vendor's software there or you probably can't use say the scanner over a network.