Re: How many instructors teach Ukemi Waza?
Teaching ukemi may have some positive aspects, but has also many negative.
Most catastrophic consequence is that the students develop a sens of "safe practice". every one goes to work next day, has to support family, so practice is easy going.We start to "pretending" efficiency of technique.
No more practice "on the edge".So martial spirit is lost. This is quite contrary to Founder teaching, he said that every technique must be executed as the last technique in our life. He also asked his students to attack him any moment day or night. His students could never foresee what will happened after attack, what kind of technique Founder will execute. Automatic response (and teaching ukemi is teachin automatic response of the body) wasn't possible. So teaching ukemi was a nonsens.
Other negatif consequence is inability of student to practice with his fellow students from other style. I.e. If aikikai student goes to yoshinkai or tomiki, he is lost. He is not able to spontanously develop a reaction to receive a technique. This is particularly true in the styles where very special type of uke mi is required(i.e.Ch.Tisser's style).
There are of course many other negative things, but only with these two, no martial spirit and no spontanous response, the way to takemusu aikido is closed.