It's funny, I shoot Canon and my girlfriend shoots Nikon. We are always teasing each other about which camera is better.
She shoots with the D7000, and if I had not already been a Canon user, the D7000 is a VERY tempting camera. Nikon really thought the D7000 out, so much so, that we have been talking about getting another D7000 as a backup once her current body wears out. (She has close to 80K clicks on it already in 2 years) She refuses to look at another camera because the images she captures are simply amazing, in terms of sharpness, color and DR.
We have spoken to a couple of people who have upgraded from the D7000 to the D7100 and so far, the information they have given favors the D7000 over the D7100. The thing that kills the 7D and the D7100 is image noise at higher ISO's. Simply put, that many pixels crammed into that small of a space creates image noise, something where the D7000 has the advantage. In fact, that is one reason why I love my 40D so much. The images are smooth all the way up to ISO 1600.
Unless Canon comes up with a new sensor that can control image noise better than the 7D or even the D7000, to me there wouldn't be much of a reason to upgrade even if it had higher MP, why? Because more megapixels does NOT mean a better image, in fact it has been proven that it can push images the other direction. I think photographiers are starting to realize that more MP are not always better.
A 8x10 print made from my 40D and an 8x10 print from my 7D are extremely hard to tell apart. So, for Canon to motivate me to switch from my 7D (which I love!) to the 7D2, it has to be a truly new, innovative camera, capable of taking noise-free images at much, much higher ISO's than the 7D, even if they kept (or eveb lowered) the MP count of the new sensor.
At this point in time, Canon simply has too many 18MP cameras to choose from that in terms of image quality, I doubt one would be able to tell any of them apart in a print.