I bought my 7D two years ago - late adopter. Upgraded from the 40D.
The new camera had impressive specs, but I honestly didn't expect a dramatic change in the pics.
But after using it for a few months, I realized that my keeper rate had improved quite a bit. Now admittedly that might not be 100% due to the new camera, but I think it contributed significantly.
So then I wondered why I hadn't bought it earlier, to be able to enjoy the benefits of the better body 3 years longer.
Well, one learns from experiences. At least I try to. So I have pre-ordered a 7D2. It is definitely an improved body. The store expects it to be in in 1 or 2 weeks.
One justification for the relative haste is that I'm off to sunny Florida in January, and I might as well have the best gear for all the photo opportunities there (especially birds and bugs, that the 7D2 is well suited for). If it were not for this trip, I would have waited a bit ... but not that much, because we are going to Maui in March!
I've got the cash, might as well use it. Only a moron wouldn't.