You imply leaving openings etc. as if you have seen me demo suburi or some such which you haven't.
Therefore I could quite easily watch videos of actual suburi practice and 90% of the time say they are merely waving sticks around. But I don't as it is a waste of time saying such things, has no value. Also, I understand their way of learning is 'the norm' in their particular style.
"You keep using that word. I donna think it means whata you think it means..."
I did want to make two quick general points (not to you Graham, you keep on keepin' on man).
As others have pointed out, it should not be assumed to be universal or a given, particularly wrt Aikido in the 50's and 60's, that a Japanese martial artist would be competent or even truly familiar with JSA. I will concede that Kendo was traditionally taught in the public schools, however in 1945 that was banned for a time, and even when it was brought back, some would argue that it had changed to me more "sporty" and less martial. (There's a good article here.
It's good to keep in mind that Kendo (and other budo taught in the public shools) were basically PE. While I personally played various sports, like soccer, growing up, I would not consider myself a soccer player simply because I had participated in that activity in PE classes. The head of my first Aikido school (Kurita Minouru) specifically mentioned that he had to make specific effort to learn swordsmanship. This was despite the fact that he frequently stayed with OSensei in Iwama and studied at Aikido hombu regularly as an uchideshi. He actually spoke of "sneaking off" to study with "a certain sword teacher" (later confirmed to be Nishio Sensei) in order to learn swordsmanship. It was clearly implied that this was a bit frowned upon even. The modern historical story of Aikido seems pretty clearly in agreement with a fairly minimal role for real swordsmanship in Aikido.
WRT tsuba, echoing what others have said, let the tool suit your practice. I don't use bokken much anymore, I mostly use shinken, but I still prefer bokken without tsuba. Aesthetically I think they look nicer and I like the way they feel. Depending on the practice however, I keep a rawhide tsuba in my bag in case I need one, some of the paired stuff we do in Icho-ryu is a lot safer with gloves and a tsuba. I think it's patently absurd to think that using/not using a tsuba is some sort of litmus for laziness. To me this kind of statement implies a general lack of real understanding about Japanese swordsmanship and bokken use in general.