I agree. Very well put. That's how I try to use atemi.
Regardless of the video and book discussed above, it was my experience that Nishio sensei used atemi in this way, too.
Primarily, he used atemi to show the attacker that attacking is wrong, thereby giving the attacker a chance to cease with it. A kind of philosophical statement, which Nishio sensei had at the entrance to every technique, taking a superior position and showing it to uke with an atemi - sort of saying: "See what I could do to you."
It is particularly evident in his sword techniques.
Secondarily, he used atemi in the ways described in 1-5 above.
Nishio sensei also insisted that aikido students need to know about proper atemi, so that the atemi become believable and functional. Otherwise they would not work as deterrents, nor that well in the 1-5 functions above.
So, when he showed how to strike, it was not to teach students an alternative to aikido techniques, but a functioning atemi deterrent/distraction/et cetera, to use with the aikido techniques.
For me, there is a purity to human-vs-human violence. By that I mean, it defies delineations, and, in the end, is what it is. As such, for example, for me, when it is time/place to strike, it's time/place to strike. Outside of that instant, I am more of the opinion that it is misplaced to formulate a striking or a throwing, etc., "position." This is because to do so is to deny the purity of violence, the "is what it is" of it all.
Thus, I'm very hesitant to compare or contrast, for example, striking and throwing ("Aikido technique"). Such formulas, for me, do not so much show an unfamiliarity with "striking" or "throwing" as much as the do with violence.
Why should a strike be able to say, "Here, look what I can do to you" and a throw or a pin cannot? Why can a stopped-short strike be a deterrent and stopped-short throw or pin cannot? Somewhere behind such positions, if you dig deep enough, lies an unfamiliarity with, or at least an unthought-out detachment to violence - or at least a method by which one may make him/herself unfamiliar and/or detached from the purity of said violence.
For me, the moral high ground cannot be found in an arsenal, however that may be delineated. For me, a viable/practical morality can only be found in a non-attachment to our egocentric tendencies. For example, to not "have" to strike someone or throw them, and "hurt" them, start to practice a life armed with a capacity to free oneself, in a moment and overall, from the spiritual immaturity of pride, ignorance, and fear, from the non-virtues of anger, jealousy, vengeance, etc. In time, your life will readjust, and in that readjustment, the times you will encounter violence will also readjust and reduce. Meaning, such encounters will all but disappear from your experience of the world, making the position of having a moral high ground within a violent encounter irrelevant - a kind of, "If you were on the moon, and you only had one chop stick, what would you..." kind of question.). Of those encounters that may be present in your life, well, they will be experienced in a clarity that contradicts the "clarity" of technical and/or philosophical breakdowns, in the purity that is violence. You will be left with striking when you strike, throwing when you throw, pinning when you pin, etc. You will only have the "it is what it is."
For me, the "difficulty" of understanding strikes in Aikido, such that formulas and positions have to go well beyond tactical or architectural considerations, suggests that the plain and simple truth is that Aikidoka do not practice striking enough. In the fact that striking is not practiced enough, comes the not-needed but very present difficulty of relating, and even justifying, a type of training that today has marked the majority of Aikido for the majority of folks practicing Aikido (i.e. Kihon Waza) that is pretty much strike-free.