Yeah, photography related upgrades would be nice to see..... How about a new AF! No not video AF, but AF for actually taking pictures The current 9 point AF stinks with the exception of the center point. Keep the 9 point, but just fix the other 8! Then just add a few mp to keep the masses interested.
I have to wonder whether the 7D's AF system will find its way into more of Canon's DSLRs. That would be a nice upgrade.
As far as IQ goes, the current 18MP sensor has its weaknesses, but it is good enough that if you can't produce good images with it, then photography is probably not your thing.
Realistically, if Canon were to improve the sensor, users would only really see a benefit with better glass. While the 18-55mm kit lens does not perform too badly, many of the other entry level lenses probably even struggle with an 18MP sensor.
I think we have reached a stage where improvements in sensors won't necessarily benefit everyone. On the other hand, improved specs are what marketing departments are looking for to sell cameras.