I second the desire for better printer support (although I have two inkjets that work now).

Better game support for the R300 cards would be nice (or how about something more powerful).

G5 memory should be at least 1.5 to 2 GB.

I'm not sure I care about firewire support.

Only one of my MDDs is an FW800 and I have an NEC firewire board on the other so I can use fw400 on either.

How about USB 3.0 support?

Better integration with UAE and JIT translation.