Sitting on the last row of Economy for over 11 hours on the tail of a 747 is similar to a Middle Age Inquisition torture! Boeing designers and engineers should give it a try, as I'm sure they've never done!
Not only the plane flies with a big inclination (to save fuel) but the way it behaves, serpenting and wiggling, similar to a boat in rough seas makes your journey impossible, and takes days to recover!
Fortunately, litle by litle, new options were coming out, far better airplanes!