"Shugyo is the only way to deepen you understanding of aikido, not sitting in some corner theoreticizing about it."
It didn't work that way for me. I improved a lot more quickly when I abandoned just trying to soak things up during class, and started going home and doing pencil-and-paper work to back it up. With my learning style -- I don't claim this as a general truth -- stuff sticks better if I have to write about it.
The first time I saw sankyo I had about eleven months of experience, but just training, no 'homework'. Couldn't make heads or tails of it. The second time, about fourteen months but the last three had been spent working on remembering/describing/
naming/comparing stuff at home. Clicked right away.
I don't personally find the general "how is aikido different from dance?" questions helpful, but I learned a heck of a lot from tackling "what's the difference between style X and style Y?" after having been exposed to both. And I can easily imagine students for whom the more general questions are just the thing to get them thinking.
I'd figure that any sensei planning to do this knows his own students well enough to know if they'll find this useful or not--or at least can observe the results and find out.