I think Eric Mead's long post is one way of approaching Morihei Ueshiba's aikido as religious practice. What I tried to do in the Touching the Absolute articles is to achieve the same purpose via a different route, not through a general history of religion, but through a closer examination of the context of Ueshiba's own time. This approach requires a close acquaintance with the history of intellectual ideas of Meiji, Taisho and early Showa Japan. It also requires a close study of what he actually wrote. Much is available, but very little is in English.
A significant next step would be to separate out the tantric and Omoto elements in his own training. If any of you ever get the chance to train with Hiroshi Tada, go for it. Tada Sensei gave a 12-hour seminar in Hiroshima recently and gave long explanations of the kokyuu training he does and how these are fundamental to aikido waza. He has changed his explanations in the years I have known him and his terminology more closely approximates to that used by O Sensei hinself.
In Hiroshi Tada you have a rather untypical (in my opinion) product of postwar aikido. He entered the Aikikai around 1950, so never experienced the rigors of the Kobukan. However, his long experience with the Tempukai and the Ichikukai was clearly an effective spiritual substitute and closely meshed with Ueshiba's own training and teaching. What you have is someone who replicated Ueshiba's own training regimen (there is real shugyou here), but emphasized less explicitly the tantric and Omoto elements.
Hiroshi Tada and Shigenobu Okumura are the only two living 9th dan holders in the Aikikai who had a close relationship with Morihei Ueshiba. Okuura Sensei is 88 and has virtually stopped aikido practice, though his mind is still sharp and his memory acute. Tada Sensei is 75 or 76 and shows signs of going on forever. Neither of them has written a book or made a video/DVD.