American is starting service between DFW and Heathrow on March 29th. Flying to Gatwick is only a pain in the ass if you have a connection to make at Heathrow. It's really only a pain in the ass if you have to fly to Africa or the Middle East from Dallas. A creative travel agent can arrange a ticket that doesn't require changing airports to make a connection.
American Airlines To Significantly Increase And Upgrade Its London Service