I have some questions that I think stem from the original question.
1)-Is an Aikido class a practice
scenario geared towards learning and understanding techniques in a controlled atmosphere, led by an instructor who has some degree of insight into what is going on? Or is it a free for all where someone attacks you with full resistance putting you in a position to execute "whatever works", hoping
that it might
be the technique that the guy in front of the class had just demonstrated? If the latter is true, then why are we even in class, that can be done on the street with a book on Aikido techique.
From the beginnning I was taught that training was just that... practice. Harmonious practice at that, except in cases where specifically instructed to resist to provide a bit of realism, or in the case of Randori. Whenever someone decided that Aikido was a contest of power and ego between Uke and Tori it generally ended up in a wrestling match on the ground, after which these same individuals became airborne for extended periods while helping the instructor demonstrate the next technique
2)-In the same way the uke benefits from partner practice by having to do proper ukemi, shouldn't he/she also benefit by learning how to attack properly, and in a controlled manner?
The people in my dojo attack as well as most that do striking arts alone (some are even sensei of striking arts). For those who have no MA experience besides Aikido, this ability has been the result of partner practice geared towards mutual benefit for both Tori and Uke. When someone attacks wrong YOU TELL THEM or show them how to do it properly.
Instructors are human, they also make mistakes, but sometimes the only way to do things correctly is by understanding the myriad ways of doing them incorrectly.
So either way the instructor guides you towards what is right, even if his execution may be wrong. I believe when one has a problem with a teacher, inform that teacher of your problem, or leave and form your own class if you know better. Aikido is the epitome of freedom of expression, and the Instructor is there to ensure the safety of everyone, especially in the execution and practice of technique.