I think I've figured some of this rumor out.

Delta will increase the Express product to include a LAS hub. 75/67's will be the high density aircraft, the new order for 737-700's serving the lower density markets.

Additonally, Delta will also try and capture additional market share for Florida. The west being fed from LAS, much of the major markets in the east getting point to point service, and the smaller markets possibly being fed via ATL.

The trick will be how to connect pax in ATL without poaching from the higher yields already going through Atlanta. So now, in some cases, high yield city pairs may have some of their connections through ATL with an Express segemnt.

The 767's still don't make that much sense to me.