You can do a lot with macros, as long as you have some codes to start with. That's why I think the 990 already strikes a good balance in this regard.

I can envision a design that simply has banks of different input types (coaxial digital audio, optical digital audio, stereo analog, composite, s-video, component, HDMI, and a 7.1 analog) that each have a unique ID (coax1 through coax3, opt1 through opt5, stereo1 through stereo 4, composite1 through composite4, s-vid1 through s-vid4, component1 through component3, HDMI4 through HDMI5, tuner, ...) and a group of eight or ten "sources" (source01 through source10) that allow for editable names and can each have any one audio and any one video input assigned to them. You would have to establish a fixed number of such inputs simply so that it can be controlled, but aside from that you'd have complete autonomy. The drawback to this scheme for a company like Outlaw (which caters to the consumer and not the custom installer) is that the casual user now has to do more to get the system working. Custom installers would be fine with it, as would more sophisticated end-users (the geek in me thinks it's a cool idea, for example), but a more casual end-user would struggle with it.