As much as I miss the juice of a big dojo and community, I do not think it works well for transmitting budo.
Unfortunately (or rather fortunately, as I would never even encountered Aikido without this expansion), Aikido has already expanded. It's a done deal.
So what can and should be done to make some sort of transmission available to the majority rather than an elite minority?
1) The senior teachers of the art have to abandon this idea of "steal the technique", this ridiculous notion that you are doing the practitioner some sort of disservice in explaining what he / she should be doing. I do not think that this is likely to happen at the topmost levels so it is the responsibility of the teachers from my own generation to do so.
2) Senior teachers must be open to outside input. There is no style of Aikido which is complete, no teacher who has the whole answer. As this thread has attempted to demonstrate, there are elements of our art which could best be investigated by looking to folks outside the art for inspiration. Then we need to look at what we do and develop better ways to incorporate these elements into mainline Aikido. Once again, the topmost teachers, with some very notable exceptions, are profoundly unlikely to do this so it is up to the second tier of 6th and 7th Dans to do this. Actually, everyone should be doing this. If the folks at the mid levels do this and the top folks don't, Aikido organization will completely destabilize as the juniors will actually recognize the inadequacies of their own teachers. So the top folks will have to get out there and develop themselves or find themselves marginalized despite the big numbers after their names.
3) Aikido should be organized according to sets of nested pyramids. The organization would be the basic pyramid, there being a number of these pyramids in a given country. Each organization would consist of a set of nested pyramids. This is true in a way right now but the next level down in most organizations is the dojo with its Chief Instructor(s). There need to be many more levels within the larger pyramid to accomplish what needs to be done which is to try to make a significant proportion of the training function along the lines noted by Chris, namely small groups with lots of immediate feedback. Mass training is the enemy of real transmission.
4) The Shihan level teachers within and organization should spend their time on instructor development. The large seminar with the "big guy" model does virtually nothing for the vast majority of Aikido practitioners. It may function to increase organizational cohesion and they may be inspirational on some level (although I could debate that; I think they often serve to make the ordinary student give up on ever "getting there") but for most folks at these seminars there is no benefit whatever. Most folks take no ukemi, the teacher will probably not even speak to the majority of the people there, and if the material is to be challenging to the seniors it will be pretty much incomprehensible to the juniors. If the subject matter is made basic enough to do the juniors some good, the seniors don't get anything new at all.
I propose that the Shihan level folks devote most of their training to small groups of similar level trainees. A former uchi deshi teacher might devote himself solely to what in music would be called "master classes". 90% of their time should be spent on small group training for groups of 5th and 6th Dans and separate groups of 3rd and 4th Dans. The Rokudans should be teaching seminars at the member dojos with a focus on developing mentoring relationships with the Chief Instructors and the senior students.
If we insist on continuing with the big Camp model, there should be training within these camps which are targeted at certain groups with specific goals in mind. Everyone does not need to go to every class. Training should be tailored and groups kept small.
5) There should be general agreement what issues are central to address each year. The Shihan and the Rokudans should meet and discuss what they see as the issues facing the membership in their training. If there were general agreement that the weapons work was falling behind, there would be steps taken to address that specific issue at the organizational level. For instance the teachers who travel around doing the seminars at the local level would focus on the issues. At the large events, there would be classes designed to correct the problems.
In this regard the strictly top down model will have to go. The folks who have the best handle on what is really happening out in the hinterlands are the teachers who do the seminars at the local dojo level. The most senior teachers should listen to the feedback from the instructors who are actually "out there". I know that this is a bit much to ask for... but perhaps we could look for a generation of seniors who can check their self importance and operate for the collective good rather than their own positioning.
Local seminars should have classes for yudansha only as well as the general membership classes. Dojo-cho should feel free to ask for training which focuses on their specific needs. They should not feel as if they have to settle for whatever the visiting instructor may feel is interesting but which may not address the specific concerns of the folks at that dojo.
Large events like the Camps should have classes each day devoted to "user generated content". In other words, the folks attending the event get to ask questions and look for instruction on areas which they find problematic. Dump the "shut up and train" model for these classes and let people express what they want to learn and what they feel their problems are.
The whole focus of the organization should be on transmission, period. The Shihan pass on what they know to the next tier down. They in turn pass it down to the tier below them. The need is for personal relationship and contact. If you take the group of seniors at the top and look at them collectively, they should know the names of every dojo head in the organization and who the senior folks are in the dojo. Every dojo has one or two seniors with whom they have this mentoring relationship. This should be a requirement of membership in the organization. There needs to be an active commitment on the part of the folks at the top that everyone gets the most out of their training. This does not exist now. The folks that get the juice are the ones who make the effort to get out and attend events and camps. In my opinion, any time an organization tolerates dojo membership in which the Chief Instructor and his seniors students do not actively participate in this two way vertical relationship with the seniors, that organization is failing in its mission. The dojo in question should be tossed out. In those cases in which there are financial issues which prevent dojo heads from training as they should, the organization should provide scholarship assistance as required. Dojos which are too small to hold their own events must network with other dojos regionally to support events collectively.
Individual members of the whole can do what they want. If they don't train, they don't test. Simple. But anyone who is a dojo head has set himself up as a teacher. If he does not constantly seek to better himself, he is guilty of fraud in my opinion. A functional organization will not permit this. Emphasis must be on the transmission of the skills to the widest possible number of folks not on growing the organization by accepting any Tom, Dick and Harry regardless of their commitment to participate.
7) Part of the function of the organization would be to expose their members to teachers from outside who have something to teach of value to Aikido practitioners. Guest instructors like Ushiro sensei appearing at an Aikido Camp should be common practice rather than an exceptional occurrence. O-Sensei invited teachers to Hombu all the time. The deshi received all sorts of instruction from outside folks invited by the Founder to teach his students.
6) I do not think that setting up an organization that would function this way would be difficult at all. I strongly believe that this is the mechanism that is required in order for anything other than a small elite of self motivated folks to do Aikido of some quality.
However, I recognize that something like this would require a rethinking on the part of the folks currently at the top of the Aikido heap. Am I optimistic that this will occur? No. It would probably take certain people going off on their own and starting fresh. It might or might not be an accepted model from the standpoint of association with Japan... If association stands in the way of the transmission, then it needs to be dumped. I do believe that if anyone actually made a good start at this, they would be successful and their success would eventually force other groups to take notice. But maybe not... Notice that much of what I propose not only does not support the idea of promoting a particular "style" of doing Aikido but actually runs directly counter to such an idea. Many Aikido teachers derive their status and even their living from being large fish in a relatively small pond. I doubt if they would chuck away this advantage easily just so that their Aikido could be better.
For some of this to happen, it has to be bottom up. The folks at the bottom and the middle must demand more from their teachers. This whole "loyalty" thing allows teachers who long ago stopped trying to keep students with great potential in thrall. It is the students themselves who need to stop cooperating in their own limitation. They need to seek out the training they know they need and they need to not let anyone tell them who to train with or what to train in. If it looks like they will start losing students, the folks with the vested interests will change, if for no other reason. Right now they have no incentive to do so.