Jeff, to add to what Eric said, there are couple of places in current NEF format which are reserved (one of them is closely related to white balance) what is it, and how to use it will take time and effort that can be spent better. This is not to mention that encoding can be changed any moment, and that format can be modified once more.
Of course Nikon prouds themselves in 25 years of software development, and they have high expectations of Nikon Capture 5 to come soon. But look at this, for example. I use dSLRs from 3 companies, and maybe will add 1 more. I really want one converter for all of them. For a service bureau it becomes a nightmare in terms of personnel training to use multiple converters. "Our preferred raw converter does not support NEF, we can't guarantee good quality of the prints"; "we have much betterhighlights from Canon cameras through Converter X then from D2X through Nikon Capture" are strong messages to customers, believe me. Russia was strongly pro-Nikon before digital (because of historical reasons). When ACR lacked full NEF support, second-market prices for high-level Nikkors dropped in Russia 20% approximately.
We expect improvements in digital cameras, but converters also are improving. Making an unreadable format Nikon ties the quality of the camera to the quality of Nikon Capture. But there are algorithms that produce sharper output, with less noise and less artifacts/moire then the algorithm used in Nikon Capture. There are methods o pre-processing that allow to extract much more details from highlights then Nikon Capture. Making camera quality to depend on Nikon Capture is essentially crippling the camera, s many Nikon Capture users do not even know what their cameras are capable of.
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Julia
