Remember, the quesstion is, "Is Uke ever wrong in My Aikido training. The keyword being My. The answer for me is NO!
An ealier response to this post replies with a "yes" to this delima by suggesting that the uke must give the same attack with a real intent in order to practice the technique in question. I find this uncouth to say the least.
How can an attack be real if it is exactly the same attack? O-sensei said it best when he explained that he never does the same technique twice. This means that there is no human way to exactly duplicate the angle, speed, motion, torque, etc., of the technique he performed just prior to attempting the same standardized technique. This came be said for uke! Uke cannot deliver the same speed, motion, etc., etc., in the attack as he did in the attack just before.
What does all this mean? Expext the unexpected! Yes, it is good for a beginners training for uke to mimic the appropriate attack as best as possible for safety among other reasons. However, if uke is slightly skewed in his perception of his attack, this is not a bad thing for my training because I should be able to handle it and it is good for me to see how the world is on the street in an uncontrolled environment. Aikido is about taking the chaos and seizing it with control and grace.
I do believe that if the uke is not attacking apprpriately that it is bad for his training but as far as for me as nage. its great!!!!
I hopes this offers a different view. Either way, there is probably no right or wrong answer to this question because it is all about how this issue is percieved by each individual and the reason behind their logic.