It may be possible that the construction of terminal changes (food court etc) have caused problems with this gate. It may not have sufficient room any longer to park certain ac ...

Yes I noticed the 'all seating' area there recently (schlepping from the AA gates).

It also may be a NW gate that they are not using as there are no other NW gates on the E concourse and they (the evil NW) are unwilling to give it up for fear another airline will use the gate for competitive flights in their markets!