I have a 7D and I don't think it is holding up where IQ is concerned. Where focus, frame rate, and buffer size is concerned, it is excellent. As for high-ISO, and dynamic range, compared to newer cameras it is rubbish. the Nikon D7100 is much, much better, though focus and frame rate aren't quite as good and its buffer is pathetic. Unless the subject I am shooting is incredibly novel (copulating eagles in front of a rainbow at sunset) I stop shooting my 7D at around ISO 1000. Above that, I just can't get the tack sharp quality I want in wildlife photos.
The 7Ds quality is soo far behind the curve that I have moved to an OM-D for everything that is not wildlife or studio flash work (because I have two canon strobes).
I don't know what inside knowledge people have that says they will absolutely make a 7DII. I am losing confidence that it will happen. The feature set of the 70D seems to mostly overtake those of the 7D. Some of the key differentiating features between them are now moved to lower 70D: micro focus adjustment, weather sealing, higher frame rate (though not quite as good), decent frame buffer. One thing about the 70D that remains inferior to the 7D is the body is plastic instead of magnesium.
Someone mentioned shooting a D800 for birds. It is a poor substitute for the added reach of APS-C. A few problems: tracking is difficult because its full-frame viewfinder makes the subject too small to easily track and focus; frame rate is bad; even with all that resolution it doesn't match the magnified resolution that the best current APS-C affords (again the D7100) with the same lenses.
Finally (can you tell I am a canon watcher who has been looking for a new APS-C camera) I don't expect to see any revolutionary improvement in dynamic range or high-ISO performance. Why, you ask. Because none of the marketing materials even mention image quality improvements. Do you think for a second that if Canon had finally made a leap in image quality that the Canon marketing people would hesitate for a second to shout it from the rooftops. Of course they would, but they've got nothing, so they are marketing their features like WiFi, swivel screen, and live preview focus performance--an achievement of dubious real-world value. Those extra focusing pixels, according to everything I have seen, have nothing to do with image capture, so they won't improve the image in any way, except to possibly improve their face-priority focusing (maybe not a worthless feature).