I don't think the Q line is dead as much as it is simply not getting the same amount of attention as Ricoh's other products. We all see a flurry of activity and then everything goes dead and silent for many months. Then suddenly everything fires back up and it all goes dead again. When I say dead I mean dead - no product updates, no lenses, no FW updates .... nothing! This pattern doesn't change my affection for the system or how I use it. I still shoot several "dead" film cameras and they work just fine.
Personally, I would love to see a longer focal length macro prime. A lens like that would complete the Q line up. There would be one of everything, for the most part. Three zooms cover from UWA to telephoto. There would be two sharp primes and a fun fisheye. I suppose some could argue for a super zoom that would go from 4mm to 20mm but I don't think I would jump on it right away.
I would love to see a jump from 12 MP to 14 MP or 16 MP but not at the expense of limited dynamic range, increased image nose, and worse color sensitivity. The lenses are sharper than what the sensor can resolve and I think 16 MP would increase the amount of details in portraits and close-up work. A 2/3" sensor would be nice if it happens to work with existing lenses. The 03 fisheye would definitely be out. I've seen uncropped 4:3 images from the Q7 and the view is like a circular fisheye. However, the difference between 1/1.7" and 2/3" is pretty small. Diffraction shouldn't be an issue. The DoF of the Q system is huge so most people ought to be shooting with the lenses at near wide open apertures anyways. f/2.8 with the crop factor of 4.7x is like f/13 or something crazy like that in FF speak. Do you really need more DoF? Shoot wide open and use the ND filter if you need to regulate the amount of light coming in. Maybe a macro application would change that ... I don't know.
The best upgrade Ricoh could perform is an upgraded AF system if the lens can support it. That, and a faster response for quasi-quick action shots.