All those millions of pixels are welcomed, I just got a Nikon D300 and I'm amazed on how less than $2k can give in so many levels, so, yes we are moving and reaping the fruits of the digital revolution.
On the other side I think that I will keep my P 25 for a few generations and this are my reasons:
* Sensel size in a P 25 class back is 9 while this newer backs will have, what? 6 or 6.8 ? It is true that there will be an improvement of IQ via "other stuff", but it may well be that the improvement in IQ over the old P25 will be not spectacular as the pixel count is.
* I am paying the thing, so this is one factor for me, my business is slow because of my personal situation as a spouse of a diplomat. The back can produce nice clean gorgeous files of 63MB size, so, upgrade is not justify just yet for me in the economic perspective. (The D300, on the other side, for example, was a perfect investment)
* I don't need a back that would work differently than the P 25. I shoot tethered, so critical review doesn't have to be done on a LCD, and the back can be used in the field since it is very robust and works un-tethered. For fast paced work I may use the D300...
* The best improvements in Digital Back will come in the form of software, so we will continue to wait for Phase One CAPTURE 4
* I only need the back to work in 50 to 100 ISO (not that the new ones will offer a lot more...)
When I finish paying the back I may be in the market for a 28mm and camera like ALPA, Horeseman or CAMBO and maybe one for studio work...