In case you haven't noticed, Nikon has now turned over their full lineup of consumer DSLRs. We have the D3100, D5100, and D7000 having been released within a relatively brief nine-month period. That's slightly faster than the eleven month period in which the previous generation appeared (D3000, D5000, D90).
Side note: The D3000, D5000, and D90 all live on at the moment mainly because of built-up unsold inventory. As inventories disappear on these items, they'll be removed from Nikon's "current cameras" list. None of these models are still being manufactured.
Some things are now clear. First, all the models went somewhat upscale in feature sets. Many of these additions are little items that aren't at first apparent (like the dual IR receivers on the D5100 and D7000, or the built-in intervolmeter and multiple exposures on those models). But taken together, the current generation of Nikon DSLRs is more feature-laden than the one it replaces. Each model has gone somewhat upscale from the one it replaced.
Sensors, obviously, have changed. From 2002 through 2007 we had 6mp sensors in the consumer lineup. From 2005 through 2009 we had 10mp sensors in that lineup. From 2007 through 2011 we had 12mp sensors in consumer cameras. Moving forward we're at 14 or 16mp for this and possibly the next generation. Despite the upward tick in pixels, there's been a pretty good progression in underlying sensor ability along the way. Today's 16mp sensors are clearly better at high ISO (both in JPEG and raw) than those older 6mp, 10mp, and 12mp sensors, for example.
Price points--adjusting for the vagaries of currency fluctuations--remained about the same. Thus, new buyers are getting more camera and better images for about the same money as before. This represents a typical product strategy from a consumer electronics company: keep price points about the same, drive manufacturing costs down and add enough compelling features to trigger upgrading as well as new customers, and you have a recipe for unit growth with no loss of product margin.
The question that needs to be asked is whether or not this strategy will work for another consumer DSLR generation. Such a generation would start to appear in md-to-late 2012. But what would it have that the current ones don't?
Yes, the feature list could be bumped a bit more, but we're already in what I'd call the marginal features realm (realistically, how many of you have actually used the Multiple Exposure capability of your camera?). Pushing more pixels into DX seems marginal, too. At about 24mp you exhaust the capability of the best lenses, and diffraction is robbing you of most of the resolution increase anyway. True, you could go the Sony route and move to pellicle mirrors to improve AF performance in Live View and moviemaking. Still, by any means you examine it, today's consumer DSLRs are more capable than most of the market needs. That makes "adding features" not as compelling as it used to be.
And then there's the missing lenses. Let's just backpedal to 2007 and look at what DX lenses we've gotten since: 18-55mm and 55-200mm updates, 18-105mm VR, 35mm f/1.8G, 10-24mm, 85mm Macro, 55-300mm. Note that we've had two generations of upscaling the DSLR body in that time frame, and went from 10mp to 16mp. Do the lenses we've been given match the upscaled cameras? No.
I have no problems with the 18-55mm and 55-200mm updates. These are key base constituency lenses that sell in large quantities at low cost and need to be done right (optically better with each generation, cost driven out to keep price down). Other than the 35mm f/1.8, which is a superb lens for its price, we haven't gotten enough other help in the DX lens department as the cameras have increased in ability. The 10-24mm was a nice option, I suppose (and I use it on my D7000), but we continue to miss a whole host of other needed lenses. At the risk of repeating myself: 16-50mm f/2.8, 50-135mm f/2.8, 16mm f/2.8 (preferably faster, but needs to be small), 20mm f/1.8, and 50mm f/1.8 at a minimum. To put it in ad-speak terms: "our latest cameras are better, so you deserve better lenses, too."
Nikon's done a nice job of pushing the consumer DX bodies upward, but we still need them to do the same with the lenses.