Interesting post. When I swopped my D90 to the D7000 I immediately wanted my D90 back! I worked very hard to tame the D7000 to meet the IQ of the D90 and finally did. It much depends on what you are using the camera for. I used the D90 and now the D7000 for wildlife and birds in flight. It took me a long time to match the D90. I actually don't like the D7000 because of the steep learning curve caused me pain, that said it is still a fine camera and much applauded by others.
When I bought the D800 it was a transition from the D700 and it was a breeze with no regrets whatsoever and the D700 was until I changed the best ever camera I'd had. The D7000 now spends a lonely life with only occasional outings.