I would have to go back and do some digging but Nikon filed a Patent for a Hybrid VF quite some time back.
There are many things I like about the EVFs for some types of shooting but for shooting fast action I have to have an OVF. I just cannot pick up a target, and track, instantly with the Olympus or Sony. With the Olympus EM1 I can easily 'de-clutter' the EVF. Sony is pretty much the same but still learning. Shooting more than one system works for me. At some point I would like to try a Fuji but it seems Fuji has dropped the Hybrid in the XT-1 and the X100T is still pretty expensive just to try it.
On my recent trip, with hours in an SUV travelling in the desert, my keeper rate from the Df, at 60+ kph was pretty good and that was with the 105 f2D, I missed having the 70-200 2.8vrII. Not even close with the Sony a7II and my wife only had a few with the EM1 and those where when we had to slow right down passing trough villages (or very bad roads).
As far as a Hybrid, just have to wait and see how it would function