From my experience, trying to show the material to others, in-person, people have largely been unimpressed. Now, why is that? Because the material is such that even if you knew exactly what to do on a conceptual level, that conceptual knowledge imparts almost zero actual ability on how to do it. It takes many years of specific body conditioning to start manifesting skill at even a rudimentary level. It's depressing, it's hard, it's disconcerting, and people who are simply not excited about the material a priori won't get why a person like me would be excited about something that I am both so bad at and have spent so much effort on just to be this bad at it.
Even when you've seen, say, some exercises to work on, it is very easy to underestimate the importance of them and why, in retrospect, they will help to produce the final outcome that is desired. There's really only so much you can say or show about them, but after you work them for some years they expose a bewildering and never-ending stream of problems to solve.
So, okay, let's take the base level of body harmony. You want a body where, everywhere on the surface, on contact with someone or something, it needs to neither push back or yield away from it. You are a mountain, still and impervious, and any force coming into you merely echoes back out - mountain echo. You're not resisting anything. You're not evading anything. You're not even moving - externally you are completely still. Your mind is being profoundly neutral, expressing itself in all directions so that none is left out at no place on your body. Everywere to anywhere else on your body, you are supported. In the limit, when you are good at just this, it makes you difficult to be pushed, pulled, yanked, thrown, tripped, etc. And how do you get there? Years and years of solo intent work, and partnered work practicing that against which you are trying to remain profoundly neutral towards in the first place - force, from your partner, uke, opponent, or whatever you choose to call whom you practice with.
... And that's not even aiki at all. It's just basic internal power. Conceptually, it's boring, but it's probably the most important thing you can ever be good at amongst the collection of skills. And when you finally get some paltry level of ability with that? Oh wait, there's more, that was just the beginning!
Now that you have a profoundly neutral body that can support anything on contact, you have to get that whole in-yo thing, yin and yang, opposing powers, expressing everywhere on your profoundly neutral body, so that any force you exert in your body, everywhere, is always balanced within itself, never escaping you, and especially never going into or away from anything.
Imagine this seesaw with two kids playing on it.
Now imagine you were to push down on the very center of the seesaw, that is supported by the fulcrum underneath, while the kids were merrily going up and down. What would you feel there? It would hopefully feel immovable, and all the while the kids are knocking you all over place with little to no effort - though I can't account for how shoddy modern playground construction might be or how sadistic or not the kids might be.
Conceptually, again, it's oh-so-mundane and boring after staring at it forever, it's just a fulcrum and lever, so every spot on your body, without even needing to move, is like the middle of an active lever supported by a neutral fulcrum. But just getting the body to do it, standing still, without having to move, motion in stillness, is immensely difficult. Then wait, you have to be able to do it while moving, and then fighting, all while maintaining that same balanced and neutral stillness in motion. And what does a body that is expressing yin and yang everywhere on its surface look like in the end? Very spirally, so thus you practice.
And, oh, wait, once you're good at that, there's still even more stuff to work on beyond that, and, well, just look at those two above things. Doing those two things alone is nigh impossible, and only because it just takes boat-loads of intensive solitary work, not a waza to boost one's ego in sight, that will leave you doubting it most days, with oh-so-many things to screw up, that even with regular supervision by someone who knows what they are doing, and even having a firm conceptual grounding in what is to be trained, it's still not going to add up to much of anything for a loooong time... So fun, right?
So what's really to say in the end? If you really want to learn it at all, you just need to go out and see a professional, and they're very hard to find by means of understanding the difficulty of the recipe. Reading some descriptions online really is never going to cut it.