However even in the learning stages, it is important to imprint on the students of the nature of a real attack and how in real life things aren't going to be so preplanned and choreographed. Have a few exercises that even mix it up a LITTLE bit to get them aware of this.
We need to have Aikido students acclimated to the physiological and psychological responses to stress. It's easy to think 'keep calm' but without proper practice and conditioning, I doubt this will be achieved especially when encountered with a situation he was never prepared for. Even if it's a little stress (and this may be a good thing actually especially in a safe environment), the student gets used to the feeling.
Great points. Our dojo does try to incorporate this type of thinking into beginners classes. There are several different ways we do this. We have worked on some exercises to get us moving "off the line" and out of the way of an attack, we have had classes focused on a comitted attack that strikes true. We do some exercises where we can choose one of several variations of a technique we are doing (changing entrance, etc). Also try to stress in ukemi that it's not about giving up, it's about having the best tactical advantage you can when being in a tactically bad position (safety and responsiveness).
Especially in our weapons classes, we stress that, even though it's wooden, it's still a deadly weapon, which helps to give a sense of realism that a strike doesn't always have.