Remember that the food service operations at DFW are actually not run by their brand name companies, they are run by
HMS Host on behalf of the
DFW airport authority under franchise arrangements. Look closely at the name tags and you will see that they work for HMS Host even though the sign says Starbucks, TGI Fridays, etc.
As far as the food goes, there are some pretty decent options over in Terminal D. Cantina Laredo is fantastic, and Blue Mesa is pretty good too.
So, you're not limited to McD and Taco Bell....you just have to look around and be willing to travel a bit.