Let me dream !
If in charge of designing the specs of future Nikons, here is what I would aim at:
1) beyond performance, consumers are looking for lighter gears ( also aging DSLR users...)
2) Optics are a large part of investment, old Nikon lenses should stay compatible
3) building Dslrs with the classical prism system is more expensive and delicate than mirrorless
4) quality of eyeview finders will continue to improve in two next years, almost surpassing most present expectations. Of course some aspects will always be draging.
5) sensors are getting better at high ISO, not indispensable to go FX to offer clean high ISO and excellent dynamic range.
6) lenses for APC or 4/3 sensors are cheaper and lighter while offering excellent performance.
Then my "Dream" Nikon in two years would be
1) mirrorless, 2 Mpix viewfinder, comfortable with glasses.
2) APC or 4/3 sensor size, ~20Mpix, 10fps, on sensor phase detection, excellent SOC jpegs
3) compatible to existing Nikon lens mount through a Nikon branded metabone speedboost type of adapter keeping all functions
4) would be of the size of an Olympus OMD e-m1 but without the protuberant grip so that I can have a light camera with a 40mm f1.everyday a light walk around.
5) I could add a vertical grip which would also add the landscape grip for better handling.
6) would have stabilization at sensor level similar to OMD E-m1 also active when filming.
7) integrated WiFi with complete remote iOS and android function through APP, GPS would be through phone.
8) commander flash, possibly with the ability to act in bounce position
9) tilt, tactile screen
with such Nikon, I would feel that I was right to stay faithful to Nikon for many years. That my D800 (once it AF issue is fixed) would still be the heavy duty gear I would use with fund souvenirs but I would have a highly flexible gear which can adapt to virtually any usage.
What is your dream ?