There are three places where a new terminal could go. Within the CTA on the only patch of ground left which is next to the proposed second multistory. It could then have a simple pier to the south stands and use the existing station for the DART and drop off area.
On the negative side the CTA can't cope with 15 million passengers let alone 38 million. All the other new stands required would have to linked by a tunnel or bridge across taxiways Delta and Foxtrot.
The other locations are either in the long term car park for a smaller development or inside Wigmore Park for the biggy but both these locations contain the towns former rubbish dump and are very toxic.
Also the local residents who bought homes knowing that a large park sat between them and the airport will kick off big time if the airport use the park although the airport would get away with a smaller development if it stayed within the airport boundary.