Always have the strange feeling that the people who are whining about wanting new camera bodies spend more time complaining than they are actually in the field taking photographs...
Possibly. I spend 8-10 hours a day every weekend photographing with my 7D. I love it, its an excellent camera, but there is no question that it imposes its limitations on the photographer. Thankfully I don't use it much for low-ISO work, I'm almost always at ISO 800 and up...but that doesn't change the fact that a ISO's lower than that, there IS pattern noise that could really stand to be improved (which, btw, would take a new sensor...not just new firmware.)
There are some other things that could stand to be improved as well. The 7D active viewfinder is amazing...absolutely love it...but there are times when I think it could be enhanced as well. One thing I would absolutely DIE for is an in-viewfinder luminance histogram. There are times when I need to adjust exposure mid-stream while photographing a bird in flight and the like. I generally GUESS at what change to make because I can't see a histogram until I have a chance to preview the shots taken...but by that point in time, the moment is past and I can't redo the shoot. An semi-translucent histogram overlay option in the corner of the viewfinder that also had a "blown highlights" indicator would do my photography absolute wonders!
So when I hear someone say that people who are complaining about camera bodies and firmware features on forums should be out photographing...I find them particularly naive, and could probably use more time with their cameras themselves. I love my camera gear, no question, I love Canon ergonomics, I love their button layout, and I love their menu system. But that doesn't change the fact that BECAUSE I use it a TON, there are things that I believe could be improved upon. That there are new features that could greatly help my photography. A skilled artist can always use better