Re: How spiritual?
"spirituality" vs "religious" segregates the matter completely.
Bowing is a sign of respect, not of worship. Which took me a while to get over due to false sense of considering it "idolitry" from very religious upbringing.
Aikido, beyond technique, focuses on refinement of a person's entire being and how he/she exists and reacts with nature and the forces (negative & positive) around us.
To criticize and judge Aikido, can in some ways be like criticising the bible... no one REALLY understands the bible completley. We all have different interpretations, different translations, and different applications into our individual life. But again, there is dynamic separation between one's spiritual development and one's religious development, even though they can & do intertwine like DNA, it makes us who we are.
Let me offer this. Many forms of religion, choose yours, offer unique ways of theory and principal to apply in one's life. Take for instance, Christ's teachings, if stricken, "turn the other cheek". Does that purely mean to stand there and accept persecution, hatred, and negativity.... or is 'turning' a word lost in thousands of years and multiple translations that could mean "tenkan"- to turn- dissipate the negative energy, offer peace, balance, and harmony to conflict, thus physically manifesting Christ's love through Aikido.
Aikido teaches us how to physically manifest our own beliefs. Why do we fail at relationships, friend ships, at LOVE... because we fear, we fear intimacy, we fear commitment, just as much as we fear the blade of a katana shomen strike. But to concur it, to accept it, to understand it, we must find harmony and balance, to enter without fear, to enter and gain another's perspective without losing our own, in essence to "irimi"...
Aikido is not a religion, but a physical AND spiritual way to improve our lives, to enter and fulfill our principals and entire self-being.
But none of us are right, we each contain a piece of a grand puzzle, without each others harmony and understanding, the puzzle is never complete, the answer is never exact.
Find the greater good of your religion and beliefs, Aikido can help you to physically, emotionally, mentally, and spiritually manifest it.
That is what Aikido has done for me. It may not be the same for many of you.