Conner is stil going to get the ball a lot more, though. It is a great idea for throwing the defense off, and gives an added dimension to the passing game. I don't expect the usage to be drastically different. They are incorporating some 2 back sets, but aren't planning on doing it all the time. It makes perfect sense, especially with the loss of AB, to get another option in the passing game that could be a mismatch for LB's on the field at times.
In the scope of the debate by the OP, I think Damien Harris being drafted in the 3rd is a much bigger concern than the Steelers incorporating some 2 back sets.