Personally, I found that the 727 with flaps extended had a much greater roll response rate on final compared to the 747.
Went straight from the 727 to 744. I think it's mainly the difference in size and mass.
Must have been a handy maneuver for traffic avoidance or Intial turn off the airways on emergency descent. I wonder what kind of g loading you impose during the high roll rate and if you encroach the load limits? Was it a recommended Boeing maneuver at all or more of test pilot and wanna be test jockeys?
Can't use speed brakes with flaps extended on a 727. It's not really a handy maneuver at all. You think you have to turn. Then you realize you want to turn faster than normal. So you pull the boards. Now you're slowing down so you have to add thrust and pull the nose up if you're hand flying. Ok, now you can start turning. Versus just turning the plane. Why would there be any G load issues during a roll? The G load is a function of bank angle if you're holding a constant altitude and not roll rate.