Hi Jun,
~~In ukemi class, we practiced the basics of taking ukemi by nage presenting us with a structure, a framework. We weren't told to take 'air' ukemi--just throwing ourselves around the mat. Well, I think that in order to learn how to learn Aikido the student must be presented with a consistant, stable, clear framework from their sensei and seniors. These are the principles, these are the fundamentals, this is how it works, this is why that didn't work.
~~I think it's ultimately time-consuming, ambiguous and frustrating to simply demonstrate something a couple of times and then cut people loose to flounder about as best they can when you've given them no understandable framework. Structure isn't negative; there is still plenty of room for self-exploration and self-discovery, perhaps more so since you have a sound foundation to reach out from.
~~Just my thoughts on an interesting topic.