I made the statement during my Photokina coverage that I was seeing more and more people giving up on DX and going to m4/3, in particular the OM-D. Since making that statement I've gotten more than a couple of dozen "me too" emails. In almost every case the bottom line was simple: "Nikon didn't give me what I needed in DX." Typically, that revolved around lenses. Small, light lenses.
The funny thing is that Nikon has their own precedent to look at. The Series E lenses were smaller, lighter lenses targeted towards enthusiasts rather than pros, and were made for smaller-than-pro film SLR bodies (e.g. the FM's). Slightly less aggressive apertures (typically f/2.8), but also less bulk and weight. It's also not as if Nikon has never made a pancake lens. Consider the 45mm f/2.8P, which sold 30,000+ units in four years, despite being a manual focus lens in an autofocus world. Nikon also can't be oblivious to how well pancakes from other makers have sold, either (the Pentax K pancakes, or even things like the 16mm f/2.8 NEX or the many m4/3 pancakes).
So the fact that Nikon has avoided "going small" in DX means they're following a particular strategy. Indeed, the popularity of the 18-200mm seems to have pushed them to up the ante with the 18-300mm. Only problem? It's bigger and heavier, and thus running exactly counter to the current developing trend. Does it really matter if the 18-300mm is a good lens or not if what some of the key customers wanted is still missing in action? I don't think so.
The problem for Nikon is that trickles tend to become streams, which tend to become rivers. We're deep into the trickle out of DX. As more and more people discover that an OM-D is smaller, lighter, has more small/light lens choices, yet is virtually as competent image wise as a D7000, what's that mean for DX?
That's not a rhetorical question, so I'll answer it: Nikon (and Canon and Sony with their APS systems, for that matter) needs to re-make the case for DX. It has to sit in a pocket between mirrorless and FX to live on. Mirrorless is becoming a complete system (m4/3 especially). FX is a complete system. DX isn't. Considering that Nikon sells more DX cameras and lenses than anything else other than Coolpix, the lack of a "complete DX" is an egregious mistake by Nikon.
So what can I do? Well, I'm declaring October DX month here at byThom. Look for a number of DX reviews and commentaries during the month. With a little care, you can fill some of Nikon's negligence by adept juggling of what's available.