It's not so much about going from full-height drives to half-height drives, but about finer details.
Disk rotation drive - when and how was the belt replaced with a direct drive and a flat motor? Who owned the patents and who launched the first major series?
Head positioning drive - what options existed besides the early "snail" and the stepper with metal tape winding on the shaft? How have the types of motor steppers changed over time?
When did the standard analog transistors and chips, as well as the digital logic of the 74 series, begin to be changed to more integrated solutions?
And further, deeper, including the electromechanical features of DEC dual drives and Japanese exoticism in the spirit of SHARP used in the X68000 line of computers.
PS Something like this could have been used as the starting material for the wanted review ...