Highly improbable, IMO, cos you would need an incredible amount of bandwidth to make this connection work well between the switch and the dock. USB C has a maximum transfer rate of 10Gb/s, normal ps4 has a bandwidth of 140 GB/s (1.120 Gb/s). To make it work, nintendo would have to completely transfer the hardware to the dock and use the Switch as a glorified memory card/card reader. Can't see they doing this, the cost would be HUGE and still way below PS4/XBO level (so, moot point). Also, with PS4 Pro already out and Scorpio around the corner, Nintendo would be shooting themselves (again) in the foot if they intend to enter an arms race with Sony/MS.
Despite all that, Switch is shaping up to be very nice (FE and Mario Kart, how can that not be good?) and with japanese portable market going strong, can't see it flopping. Of course, if you're looking for power and couch gaming on current gen level, better look somewhere else. To me, PS3/WiiU level games on a portable is good enough. Also, Nintendo's only chance of doing well in this gen (again, IMO).