What the prequels didn't have was a producer like Gary Kurtz (IV, V), a screenwriter like Larry Kasdan (V, VI), or a director like Irvin Kershner (V) -- people who could disagree with Lucas or at least present another point of view.
Stop drinking the Kurtz koolaid.
Kurtz may have been a positive force creative wise for ESTB, but the problems as a producer including budget and scheduling woes laid at his feet was what got him sacked from his job.
In fact the problems with the production of ESTB ultimately was why Lucas decided to end SW at Jedi instead of going with his original plan of cranking out SW movies every few years. And also probably why Marquand on ROTJ having such limited creative control.