On topic, the big question I have regarding 9/11 isn't as much the sequence of events or how they necessarily occurred; but to begin with, why the events were able to occur and why we suffered such a gross intelligence failure, the likes of which haven't been seen since probably Pearl Harbor. For the amount of intelligence capability we possess as a country and for the amount of gathering organizations we have (CIA, DIA, FBI, NRO, state/local, for example); be they military, law enforcement, etc; I have a hard time believing that it was any sort of incompetence or any sort of "we just plain missed that". The puzzle pieces were there, albeit scattered. On one hand and to be perfectly fair, intelligence gathering and analysis is a tough science and isn't perfect by any means. But at the same time, we employ alot of smart people whose sole job is to analyze data gathered in the field by whatever sources, and essentially spend their time "putting puzzles together". Looking back at a number of indicators that were seen, some of them pretty high profile, I want to know why those were minimized or written off? Of course, if anyone had told me on 9/10, exactly what was going to happen the next day; I'd have thought they were off their rocker. However I at that time, didn't have the various pieces of intelligence that had been gathered yet seemingly put on the backburner by some senior people as something less-than-important and/or to be left for later to deal with.
Those are the questions I have, to begin with. Because that intel failure of ours is key to the weaknesses that the hijackers supposedly exploited.