I doubt that the security checkpoints in each arm would ever be put in because that would be a major inconvenience to all connecting traffic. Imagine having 15 minutes to go from the end of the A concource to the B concource and now security is thrown in. I have never been to MCI, but I think something similar is in effect there and everyone complains about it who must connect through there.
As for the airmall, I go there a few times a year to shop and eat just for the fun of it. A few more times to meet and eat with family and friends who are departing or arriving. However, I am now restricted to ONLY going there the handfull of times that I actually get on an airplane. I think that the shops will lose AT LEAST 1/4 of there revenue because of this, but I personally think it will be a much higher amount than that. I hope this new setup is not permanent because it will have very bad effects on the AIRMALL.
If US Airways moves out, I think it will be very desolate at the airport for at least a while. However, someone would have to take over this state of the art uncongested terminal. Plus its location is almost ideal for all connecting airtraffic in the East Coast. Of course AirTran would be a possibilty to take over. Maybe if Continental gets too ticked off at CLE they might move down south to the awesome PIT terminal. I also for some reason see American as a prospect for moving into PIT because of their lack of a really strong and convenient east coast connecting hub. One thing is for certain, this state of the art terminal will not be let go to waste.