One thing that does stick in my craw a little is
2. That Daito-ryu was not taught in the kata form we see it. In fact, Sagawa states that the "numbers" of kata in the various menkyo were, more or less, because Takeda thought those were lucky numbers. Arbitrary, in other words (which would suggest that the kata were placed on the "matrix" of the numbers later - by someone(s) else, yet another of my speculations.
I am not so sure we can glibly say that something like the Hiden Mokuroku was arbitrary and fluid. From what little I know of various branches including "aiki budo" era aikido I see a remarkable consistency of technical content.
I also counter with Sagawa's statement that Takeda had an excellent memory and could pick up where he left off the next time he taught a student. Remember that there were thousands of students and he would only show up from time to time for seminars. Sagawa didn't say he would show new arbitrary stuff, the statement implies that Sagawa knew what the order was and observed Takeda picking up where he left off without repeating. You will also recall that he did the same thing at Asahi News, saying that Ueshiba has only showed you up to a point and he started teaching from that point.
Not really a big deal, but I would find any theorizing that used a lack of technical syllabus on Takeda's part as a starting point rather suspect.