You already realize your problem now - it is your location which is much closer to DL's fortress hub of ATL but far away from other airlines hubs. CO has higher miles level redemption with better availability too but the issue is CO does not fly the routes that you deem convenient from your home airport - that is the crux. CO on the other hand would be very convenient for folks live in NYC area because it has tons of flights from EWR. Or, for that matter, Houston is a good fit. Folks live in either Houston or Dallas would have easier lives when redeeming either CO or AA because the 2 cities are not that far apart - just a few hours drive and people are willing to go that distance if needed to be.

However if you insist on the convenience from your home airport, then them's the break.

No way CO miles are given out like candy in the form DL miles have been given out in the past few years via the double miles in every $ spent for the longest period on the AMEX cards when DL basically sold tons and tons and tons of miles to AMEX in order to get cash to tie it over during the hard time but at the end DL still filed bankruptcy. Ironically, of all the legacy airlines only AA has never filed a bankruptcy and tried to protect the work force's benefits - they are now under the heaviest burden of labor costs due to other airlines all nullified their pension plans and compensation contracts etc and greatly reduced their labor cost burden.

The CO miles you see given out are just the one-time sign up bonus, but the DL miles in the past were given out on the spending at 2x 3x rate for several years! Major difference if you do the math which surely not hard for you to do given your prior professional life.