Aikido and Spirituality? Isn't that like trying to find all the magicians secrets in a one sitting?
The new society of modern man has tried by all scientific means to explain all phenonmenon. Sometimes it is impossible with the tools at hand, or the knowledge being used to pick apart the magic, but in the end, the impossible becomes the improbable which can be defined while the impossible just takes a little longer.
There are training techniques that found in different cultures around the world that give superiority to fighting skills of that culture, yet, when we try to explain them without the proper experience, or knowledge, it becomes same as the magicians magic trick. There are ways to strength or weakness you carry with religious spirituality without knowing the scientific reasoning that causes such phenonmenon. Although there are sources and tools in the last ten years that are beginning to measure this energy, and explain why certain aspects work and others do not. These tools are being used to search for the scientific reasoning so that we can learn the boundaries of physical manifestations of Chi/Ki verses the introduction of religious spirituality into Aikido as a means to understanding the powers found in the world we live in, and how we can use them for Aikido?
It might be as simple as understanding some of the modern conveniences we have today, compared to horse/ buggy / kerosene lantern of yesterday? Or, in the sense of using the spiritual approach, you need to have the right attitude/ state of mind to be at one with the universe?
I think, you will find that the balance of the total package of understanding the forces that improve your physical, mental, and natural control of universal elements we are just starting to understand will be your personal journey. How you percieve the understanding of these elements to gain balance and control will be up to you.
As far as the journey of O'Sensei ... we can not know the personal demons that his life carried, opposed to our own, but somewhere he found the strength to conquer them, and give us a glimpse of a better Martial Arts life beyond that of one dedicated to killing, showing personal greatness by combat, or just plain tell us that the UNIVERSE was held together by LOVE? Eventually, all religions and spirituality should reach this basic tenant. What we do with it when we get there ... now there is question to ponder?