I'll put is simply:
Uke role is very complex, being a good Uke is not trivial
Uke main role is too give the proper feedback for Nage. However, while doing this, Uke is also learning himself. Even if we constrict ourselves to the main role - the feedback, one should notice it should has several characteristics that sometimes conflict:
When practicing Kata \ Waza (pre-defined attack and techniques) giving a realistic feedback is not simple by itself. Uke knows the response, and many tend to slowly adjust the attack to make Nage job more difficult. I have seen more then one person who has done this unaware.
Making the feedback educational is also not simple. People learn optimally when their fail rate is around 1 in 4. If a person only fails, he will not learn anything, if he only succeeds, he will learn nothing either. Further, one can only absorb that many corrections in a given time period.
Uke should also keep himself safe, and prevent injury. Thus, one could not wait until a technique is executed in full force and speed to examine it. One has to respond in a scaled down version -- reduced speed and force.
Combining these together and adjusting the feedback for each person one is practicing with is an art by itself, at least as complex as being Nage.
Since being a good Uke is such a difficult task, there is no point in punishing those who fail it, after all, if you look closely enough, you will find none of us is a perfect Uke. This does not preclude educating a person through physical means, which could prove instrumental for some people.
On another issue:
Xu Wenfung wrote:
Randori or jiyu-waza is the place for testing your "str33t effectiveness". This is also the place where uke is allowed to come to attack in any form he wishes or those determined by the sensei, this is the place where tori is allowed to transition, atemi, etc to work on their fighting skills.
This raises a thing my teacher keeps pumping into our heads in every other practice: Randori is not a simulated fight, Randori is another means of learning. In a street fight, it is the end results that is important -- either you live in health or
. On the other hand in Randori, the way you get to the situation of the technique is the important thing, forcing your partner down is counter-productive.
True, Randori is much more open for spontaneity, but this does not make it a fight.