Bottomline, MSY-DCA fares allow ORD, CLT, DFW, LGA, and PHL connections according to the fare routing rules. No, it's not reasonable to request they send you on some wild routing around the US due to a waiver. An overnight in DFW will create a fare break as the maximum layover allowance on domestic fares is 4 hours. They have some more flexibility in IRROPs, but in a waiver situation like this, they aren't going to bend over backwards for you.