Aren't there long term plans on the table to widen the concourses at ATL? They could certainly use some additional space, especially in the gate waiting areas. A moving sidewalk down the middle of them could also be an added plus, of course this could only be done if they were expanded. Concourse D is especially narrow.
It is not possible to widen the concourses without tearing down revenue generating shops, and I doubt AATC and the City of Atlanta will want to see the loss of revenue. As for Concourse D, they just need to tear it down and build a new one. A, B, and C were built with Delta and Eastern having things built to their specifications (which is one of the reasons why there is an underground walkway between B North and C North, as Eastern wanted an express connection between their concourses). With the other non-international airlines getting lumped together over on D, there really wasn't much input into the design in regards to the other airlines. Republic and Piedmont were the biggest airlines on D when the Midfield Complex opened, the airlines on D really paled in comparison of the operations out of A, B, & C.
[Edited 2004-07-15 23:40:06]