Almost everything, taken by itself, can be argued away:
Oswald defecting to the USSR
Oswald returning from the USSR.
His mysterious handler, DeMoerenschilt(sp)
The suicide of DeMoerenschilt the day before he was to testify in the 70's.
MG Edwin A. Walker being fired by JFK in April 61. A lot of people don't know this but Walker was about to receive his third star at the time he was fired.
Walker's behavior and associations between April 61 and Nov 63. He hated Kennedy with a passion.
Oswald firing a shot at Walker in April 63, And this fact not revealed until the Warren Commission Report.
Oswald being in New Orleans around, what appear to be, mob figures, Cubans and possibly rogue elements of the US.
The rush by LBJ to get the Warren Report out before the election of 64.
LBJ personally tinkering with the motorcade route in Dallas months before Nov 63.
LBJ's insistance that JFK's body be on the plane back to Washington.
Jack Ruby's association with the mob in some capacity.
The Warren Commission's refusal to bring Ruby to DC.
All of these points, and countless others, can be debated and dismissed. For me it comes back to the question of who stood to gain and who could put a hit into motion. If one looks at LBJ's political life before Nov 63, most would agree he was beyond driven. He had a ruthlessness and an ambition that could be defined as blind. In a sense, LBJ appeared to seek power in much the same way as x42 did. They used different MO's but both sought power for power's sake, IMO.
I, for one, am not ready to explain away the unanswered big picture of the 60's anymore than I am ready to explain away all that happened in the 90's