Resetting IO is something we have all(mostly) learned to deal with. Every time I open a session from another studio, the first thing I do is open the IO setup and make appropriate changes, as well as delete any bogus routing on the BUS tab. You could also create a new IO setup with names that correspond to the imported sessions(save your current settings as your default for when working on your own sessions). If its always(or usually, anyway) from the same outside source, you could name the main outputs on both systems to the same name, and that should make the main outs come up working. When I had my 2-room facility in Nashville, the midi room used an Mbox 2 Pro, while the main room ran a 64 IO HD/Native rig. By naming the normal output on both systems to "Main Out", sessions would move back and forth with no fussing required
I agree it would be nice if it would magically "fix" itself, but given the unlimited possibilities in routing and naming, I'm not sure that's possible.