While I can't really say this qualifies as a "nightmare" in my book (I'm guessing you've never actually flown through DTW and are assuming the airport somehow resembles the city of Detroit), Rule 240B in Delta's Contract of Carriage provides for a full refund for schedule changes that result in a 90 minute or more change in your arrival or departure. Since you seem very concerned about getting the shortest, most direct routing possible, it sounds like you would be better off getting a refund and going with US Airways as they seem to have the most direct routing options (via it's hubs in PHL and CLT).