Seriously - with Mesaba and Pinnacle being existing carriers with crew space and offices etc... taking up most of B and C there is simply no room for Compass on B/C. A few years ago the Avro operated by Mesaba would park on A and B and that was a nightmare. It's so much easier to organize the operation closer together.
I can't help but wonder if that will change when CO is no longer in B/C.