"It would not be correct to say that my Takumusu Aiki emerged from religion. True budo illuminates religion. It guides incomplete religion to completion."
And what is his idea of true budo?
My art will not be recognized as a true budo and will not taken seriously without power.
And here I think that Ueshiba is pointing to something important - that his spirituality was completed, given substance, through his budo training. Not the other way around.
Western philosophy/spirituality tends to start with an idea or an ideal. That's a good thing, and an important thing, but without some way to get there all you've got is - happy thoughts and pixie dust.
"I know of no other way to reform the world than through Aikido."
It was Ueshiba's martial training in Aiki that gave substance and reality to his spiritual ideals. No Aiki = No Spirituality
Think about it. How hard is it to really change something about yourself? How many people can successfully do something as simple and superficial as losing weight or quitting smoking? If changing an external habit is that hard, how hard is actual fundamental change going to be?
Happy thoughts just aren't going to get you there - it requires extensive conditioning over a prolonged period of time. Ueshiba found it in Aiki Tanren.