The 10 pin connector is mounted on the front of the body to the right of the lens when you are looking at the front of the camera. If you are using the camera on a tripod, with an L-bracket in portrait orientation, and have a remote cable release/GPS or other accessory conencted, that placement does not interfere.
On the D700/7100 etc,the remote/GPS/accessory connection is on the left side of the camera, behind the rubber door. A accessory cable connect there sticks out so far that you cannot use an L-bracket mounted on a tripod in portrait orientation.
Most Pros use L-brackets because of the simplicity and speed of reorienting the camera.
The point may be not so much the 10 pin connector as the location of the connection, although I do find the 10 pins to be far more robust and unlikely to accidentally disconnect.
The pro bodies also have a pc-sync connection just above the 10 pin connection. Although perhaps less useful in these days of radio triggering of flashes, it still comes in handy. To do the same with a D7000/7100 etc, you need to buy a Nikon AS-15 to mount in the hotshoe.
Pro bodies simply have more features designed to make the pro's life easier.