Re: Beginners should not be allowed to act as uke.
It's nice sentence in the beginning of thread but it looks like game with only one goal. All talks are about how to make training more effective for rookies. However no one mentioned about seniors training in that case.
Pay a lot attention to rookies is important to keep their interest to practice. Even in such case some of them quit practice maybe next week or next month. So bet on rookies isn't good time spending, IMHO. They don't prove the seriousness of their practice in one week. On other hand is seniors who had to practice with guys "near by zero" level. How they suppose to increase their skills with rookies? I know "rule" how to increase own skills. It's "if you'd like to be more skillful you had to practice with guys that more skillful that you are now". Obviously that for rookies practice with seniors is the best way. Seniors get a bit more than nothing of that. Yes, it's totally selfish wish to be better than yesterday, but isn't budo created as a tool that makes you better?
I found one way to solve this problem. Rookies start from basics of the basics like ukemi and other that they could do without a partner. Friend of mine had half year ukemi, taisabaki, atemi and combinations of taisabaki and atemi at the beginning of his aikido practice. Of course there are many more exercises in aikido to build strong basics for techniques. And rookies have time to prove the seriousness of their wish of long term practice.
Proper ukemi and attacks are keystones of this as I call it "rookie course". Good ukemi serves for safety in further practice and attacking skills they need for correct techniques. Both of it's make at least good uke from rookies. Another friend of mine spent few months to ukemi only when he had started judo. After that group has kind of ukemi test -- coach throw all of them few times. Students with good ukemi starts practice but students with not so good ukemi continue with it.
Back to the problem as far as guys becomes good uke they should start to practice in pairs. This is nice time to the most skilled senior to lead them and show them "pictures" of techniques. Why it's only one person? Different persons with different personalities have different points of view to aikido practice and pays attention to different things. As for me the worst thing to rookies progress been taught by different persons. They started to know many but did nothing solid. Senior has rare chance to try skills on guys who don't know "rules of the game". It helps to improve senior's skills also. The last step is mix group of new students with seniors. It moves new students from "picture" to ideas of techniques. Different seniors shows them rich field of different points of view to ideas.
Of course I don't think that such program will be popular and draw a lot people into training. I only think that it helps to create students with good enough skills.