It is a huge improvement and the RAF were very remiss to disable it
The reason the RAF got rid of the system was because crews would regularly beat the system. If you were hitting a merge with the wings back, as the speed started to decay you would move the wings forward so that they arrived in the right configuration as the speed was reached. Same with maneuvre devices. If you knew you were going to turn you would put the slats out in anticipation. The automatic system had to react and so it was felt you had perhaps lost a bit of 'edge'. The OEU did the trial to quantify the performance.
The promised improvement, WASPMD - 'The wingsweep and slat pilot's mindreader device' never came to fuition.
Ghost