I would like to make comment here.
The experience of duality dissolving into unity: Isn't that the meaning of harmony? Part of the word Aikido. So when you see some Ki Aikido for instance you see Aikido expressing that no?
Now, many may see it and not get it and not see how it can be martial but there again many see it and see how it can. I often wonder and indeed ask if those who go against it can do it. 99% of the time they cannot. It's a skill which takes a lot of developing.
So even if someone is just learning to go along with then they are learning some valuable lessons in that alone for that in itself takes concentration and mental discipline. They at least are getting a glimpse of what it is like to harmonize so I would say it's essential for only then can they see what they are aiming for, to be able to do in more and more difficult situations. Keep going on that path and you would end up harmonizing with the most dangerous and fierce situations too. This is one way of looking at Aikido and I meet many inside and outside of Aikido who understand this. They also understand how that would take quite a time and lots of discipline.
Some Aikidoka have a consciously spiritual aspect in their Aikido but generally I have found this is not the case.
I have met some from other arts including Karate who are usually people who have been doing them for many years but then they start seeing the spiritual basis of even those arts. They too then bump into telling others yet not being understood by many for they can't help to see their art from a new, different perspective. I read on here recently how surfing can be a spiritual path leading to satori even.
So in my experience there are some approaches that have the required elements to be called Aikido.
Ahh, the question. Connection between martial prowess and spirituality? To me the answer is obviously so. The reality of this can only be gotten by doing it in such a way and demonstrating to yourself.
I find Aikido as an art is so all embrasive that you will find people doing it for all kinds of reasons and thus trying to do all kinds of things in their practice. Why not indeed? It has been so since time immemorial in all martial arts. That's reality and a reality that is missed by those who shout it must be for 'blah'.
Sorry, but I can't seem to be able to connect your reply to my questions - although I appreciate the attempt. I'm sure it's me but I am left with the same feeling I got when I read an old definition of Transcendentalism as expressed by a New York lawyer:
"Transcendentalism is two holes in a sand-bank: a storm washes away the sand-bank without disturbing the holes."