It is my understanding that all the deliveries this year are "going to ORD." Now, that does not mean that ORD gets all that flying. As it was explained to me, all of them will begin or end the day in ORD or will pass through ORD each day.
For instance, we have heard (no confirmation) that at least one new 73 will overnight in STL. The first leg each day will be STL-ORD.
I have heard nothing about them converting the existing 73s to the 160 pax configuration.