The obvious question, one that Morley doesn't answer is: "So, what happened to Schlesinger's proposals? Where did they go?" As anyone who has read a history of the JFK presidency - Dallek, Reeves, et al. - knows, Schlesinger was known for turning out memos from his cubby hole in the East Wing of the White House ("With the women" Rusk described it). Many were brilliant, smoothly written, good ideas; but some were eye rollers. Reeves says that JFK would sometimes get exasperated by them.
Schlesinger was a junior aide and not someone with any authority. He was more than a court historian (at least inside the WH; but his writings later about what went on were a series of apologias) but his power was intellectual, serving JFK's ego, protecting the president. I don't think a McCone or a Helms or an Angelton would be worried about such suggestions, which apparently went nowhere anyway.
To cite this memo and argue, as Morley does, that "The origins of the CIA’s role in the tragedy of November 22, 1963 as found in the last of the JFK files" is sheer hyperbole. But who's surprised anymore about Morley's serial exaggerations? It's all he has now.