korayus: On NikonUSA site D4 has USB 3.0 connection:http://www.nikonusa.com/Nikon-Products/Product/Digital-SLR-Cameras/25482/D4.html#tab-ProductDetail-ProductTabs-TechSpecs
Yes, this is interesting.I checked the same info from http://www.nikon.co.jp/ (in Japanese). I found that the USB interface of D4 was High Speed USB (USB2.0 not USB3.0) and wired Ethernet was mentioned.I think they changed the interface at last minutes.Did they make a right decision? It is hard to say.As the targeted D4 users are high-end professionals, the choice may be right.
I'm not a fan of mirrorless cameras, at least, it is too weak for real camera jobs and too expensive and too bulky to replace point-and-shoot cameras.However, now Nikon has 1-inch sensor.I'm hoping that in the future Nikon produces something like P9000 (fixed lens) using this 1-inch sensor (the lens would cover something like 24mm ~ 150mm). I think that kind of camera would be a nice second camera for serious DSLR owners (travel camera).Not all serious DSLR owners want to carry around heavy DSLR all the time.BTW, I just made an order of P7100.P7100 is probably "good enough" for most occasions.