...and not the anticipated 0.5 stop increase in DR (read: better shadow quality, better performance at each ISO).
The 0.5 stop DR improvement intrigues me. It might not sound like much to most folks, but to get it out of essentially the same FTF9168C CCD as used in the P65+ would involve quite remarkable figures for sensor readout noise.
Readout noise would have to fall from 11 electrons to 7 electrons, a new record by some margin for an MFD sensor!
Sensor+ pixel binning further halves that to 3.5 electrons effective readnoise at 15 MP resolution - now that's getting into CMOS DSLR territory!
Reduced readout noise would indeed yield "better shadow quality, better performance at each ISO".
So to answer the OP's question: in my view, coupled with the long exposure ability [yay!
], that would be worth it.
But but but!!
There is another way to get a 0.5 stop DR improvement: increase the full well capacity from 50,000 electrons to around 75,000. That would give an electron density which is impressive for a 6-micron-pixel class device, but still similar to the densities achieved in some older Dalsa CCDs with 9 and 12 micron pixels.
That unfortunately would do nothing for ISO performance, or shadow quality in a given exposure time...
So my query is, Doug: are you certain
that the DR improvement is all at the shadow end? Can you point me to some information from Phase One or Dalsa which confirms whether they improved the readout noise, or the full well depth? It's really important that we are clear on this question.