... I wonder if O Sensei reached a point where he figured people tend to do and see what they want and in certain regards started leaving people to their own aims, since they often do that anyway. Perhaps he felt as long as a handful of people maintained the "heart," it was ok if so many other people, who were essentially interested in other goals than his, did something a little different. His principle of developing yourself first, then your household, etc. suggests that at times he was probably much more concerned with his own role in the Universe than that of others, including his own family to a small degree; leaving it to them on some level to sort things out for themsleves.
This ties into the idea of "monomania" insofaras his personal training probably took greater importance than that of his students; that his training seemed to be part of his spirituality implies to me that it was of the highest importance to him, to the point where circumstances probably meant occassionally excluding other very important aspects of his life.
I think any person has to be considered as a total being and the insistence so many people show on dividing his martial devotion from his spiritual devotion seems like a mistake to me. It results in dilution of his serious martial commitment (in their minds) and this leads them to pass on something that is neither his real spirituality nor his real martial practice, as they try to pass off Takeda as someone of a lower character whom Morihei had surpassed. He may have been a nicer guy than Takeda, but I don't necessarily believe that. Each man was what he was. Actually, to me, Omotokyo seems more or less like a cult that Morihei strongly believed in. I'm not sure it really added anything. He was a devoted person in his heart. Omotokyo just gave him something to be devoted to. And aikido was neither daito ryu nor Omotokyo. I'm content to accept it for what it is rather than trying to extract ores that it doesn't really contain.
I do think he was pretty monomaniacal, like any great artist. Some like Van Gogh, show it to an extreme, while others, like Picasso, are able to live with it.
Best to you.