The answer to the question of whether weapons should be a part of aikido training is pretty obvious on my part. After all, I’m an Iwama style student.
What would have become of my aikido without the style and the weapons? I moved to Lake Tahoe in 1976 two years after starting aikido (1974). I was a 2nd kyu. In the day, it wasn’t unusual for brown belts to start classes, and I did. Didn’t ever, in what turned out to be normal for my aikido career, have many students. Most nights I had none. So, what was I going to do?
Saito Sensei gave me the tools to train on my own, and weapons have always been a major part of that. So, my typical keiko, even today, is to do some stretches, ki exercises, hitori geiko (assuming that I have a partner and going through techniques without one), and weapons. I never knew until you recently produced the Tohei video that I owed the ki exercises to Tohei Sensei (through Alan Grow, an early teacher in Oakland, California). The bad part of hitori geiko is that you don’t have the resistance and mass provided by a partner.
The good thing is that you don’t rely on that mass and resistance for balance. That improves posture, something that I saw demonstrated early on by Kisaburo Osawa Sensei when he came to California in 1975. Erect posture not only gives the outward impression of confidence, it actually instills it.
In the day (19’76-81), I spent two weekends per month in the San Francisco Bay Area taking every class I could, but without the weapons, could I have built strength? Would I even have continued to train? Without the weapons, would I still have strength or continue to train?
This is to skip over the salient virtue of weapons. They are the perfect training partners. They give completely honest responses to your movement without any chatter. They leverage and magnify your mistakes so that even you may be able to see them.
The same principle applies to sword (tachidori) and jo taking (jo dori). The techniques are only slightly different from normal taijutsu, but the additional threat implied by the weapon puts pressure on your everyday technique, magnifying the glitches. Fix them in weapons taking, and they will fade into imperceptibility in unarmed taijutsu. That goes double for weapons partner practice (kumitachi, kumijo).
I’m sure it is possible to do a lot of aikido, learn a lot and even achieve advancement in rank without weapons. But to say that neglecting weapons is a good thing sounds a bit parochial to me.