LBJ: minor president by accident, or great tragic figure?

From the most dramatic section of the LBJ bio The Passage of Power (Robert A. Caro), Caro proceeds to the most dry section I'm afraid: after recounting in detail the scene of the JFK assassination from the point of view of the rising president Johnson, Caro brings the story back to Washington, where, in his inimitable way, he absolutely overwhelms us with detail in his account of the first few days of the Johnson presidency - reading his account of the days probably takes more time than the events covered - like a map bigger than the city it's depicting. Unsurprisingly, the first days of the Johnson administration were more or less ignored by the media, as the only story was really the mourning of JFK and developments around the Oswald shooting. As that dies down, there's a little more interest in LBJ trying to retain as many Kennedy staffers as he can - through his legendary powers of persuasion. He's also thinking about how to make his own legacy and looking ahead to the 1964 elections - so he's building up his liberal creds (and it's quite believable that he was a true 60s liberal, on domestic issues - he came out of the New Deal and it seems he was genuinely moved by the plight of the impoverished and by the victims of racial discrimination - for all his blustering, Caro never calls him out for a racist or anti-Semitic comment, which is far more than one could say about many other pols of his era, Nixon in particular). Johnson begins planning how to get Congress to act on civil rights - some of this planning very arcane, but the overall picture is clear: Johnson building on the good will people around the world held for the late Prez - he's taking on the mantle, and in the process building even greater animosity between him and RFK. Caro does a damn good job with his material - it's obvious that the Kennedy's are the more dramatic and dynamic characters, but he keeps pushing against the tide, making his case that Johnson himself was a figure larger than life, a great but tragic leader - and not a minor president by accident that most would have probably confined him to, had Caro not taken him on for his mangum opus (or opi).