My contention is that the 7D is so good as it is that there really isn't much to improve on it, except possibly in the arena of video autofocus.
Which is to say, I think the 7D has the makings of a classic the way the 5D classic is, well, a classic. 
So here's the question to the forum: is there anything you can think of that Canon will be able to do in the next 2 or 3 iterations of the 7D line that will make for a truly compelling upgrade from the current-generation 7D for someone who shoots still shots?
For me, I can't think of a thing that would be compelling. Yeah, there are some things that could be improved, e.g. low-ISO cleanliness (e.g., make the low-ISO performance when examining 100% crops equal to or better than that of the 5D classic at the same ISOs), but I don't see those things as being truly compelling.
So what do you think would make for a compelling reason to upgrade to a 7D successor for taking still shots (i.e., video improvements don't count for this thread)?
Edited to add: note that I don't really consider changing the sensor for a different sized sensor to really be a valid response here, because doing that would essentially create an entirely new camera (or, if the sensor is full-frame, another entry in the 5D line!). My intent with this question is what, if anything, Canon can do within the 1.6x crop family that would make for a compelling upgrade from the 7D for still-shot photographers.

