Do you think Ueshiba might have been chanting to reach a natural "high", too? If training sort of affects the mental state of mind, maybe Ueshiba really was feeling like he was the universe. Some people meditating/chanting have said they felt like they had a buzz or that they felt like they were floating above their bodies.
Sure, that's a common usage of chanting - and he used specific chants to channel specific mental states. But I wonder if that works so well without the same or similar belief system in place, or at the very least, an understanding of what state you're attempting to invoke with each practice.