Re: Ever changing Aikido
James, quick question, is it your syllabus training that's changing or the non-syllabus work?
Paige, disagree, it's not just boredom (although I'll plead guilty to the odd "I can't stand one more standard kotegaeshi, lets try something different"). For me, there are two areas which bring in changes. A decent teacher is learning all the time as well and this can change the way you address a technique if you find one aspect that needs specific work or can be done more efficiently. As Amir said, this change in emphasis can also be caused if you spot a particular "problem" occurring in the class (lazy turns etc.)
Secondly, if you're teaching a mixed kyu-class which you can't break into smaller similar-ranked groups, you often have to teach the same technique with a totally different emphasis depending on which grade you're mainly directing the teaching to. This can also lead to the technique changing its emphasis.