Red in STL
Turnover not takeover
You might find Midway and Southwest better for KC than ORDWell, the big factor is whether or not we drive to O'Hare. We used to fly out of our home airport (South Bend) and since SBN only flies to a handful of cities as I mentioned, our trips always began with a connection to O'Hare. The flight from South Bend to O'Hare is 16 minutes. Literally. It's so stupid.
It's easier to just drive to Chicago and fly out from there. A flight to Kansas City from Chicago would only be about 90 minutes.