Re: Why no tsuba?
Wow this thread is 10 years old. Interesting.
Some schools such as Itto-ryu use the tsuba in their kata. Other school such as Jikishinkage-ryu do not (well at least not until kodachi anyway). If you don't use it why put it on there?
It seems that "aikiken" has a very broad meaning like kenjutsu or jujutsu and what you do depends on your teacher and your training. I've noticed many aikiken systems allow the students to use any bokuto they want, and they are often made out of exotic woods. More formalized fencing systems could not allow that. For example if you tried to use a Yagyu Shinkage-ryu bokuto (thin as a toothpick) for Jikishinkage-ryu (the bokuto is like a very thick axe handle) you'd have a lot of broken bokuto. Stamp that and reverse it and you could never train with the speed and accuracy you'd need for the kata.
I would just do what my teacher told me was right. When in Rome do as the Visigoths do. No wait...