Re: Ki is Kindness.
Please call me David; "Charles" is a name I don't use, but rules is rules 'round here, so ....
I think being able to "relax" and access the kinds of physical performance associated with that (including aikido techniques done in that manner) does not require an intent to be kind.
In fact, if you find a really, really bad person, who enjoys inflicting pain, you may find they are quite relaxed and even enjoying themselves -- they get their fix giving pain, the pain is flowing, and so, to them, it's all good....
Takeda was famous for both his martial prowess and other reported talents, including being able to read another person's intentions, much in the same way you'll find O Sensei credited with seeing into a man's heart who bowed to him, hoping O Sensei would respond and give an opening for an attack....
But in him, this "talent" appeared associated with extreme distrust -- the kind of attitude that would enable one to be on guard against ambush and assassination. With Ueshiba, he projected a quite different persona. (But do keep in mind his position as a bodyguard in the Mongolia expedition).
O Sensei reportedly said that Takeda opened his eyes to true budo, but that O Sensei discovered "aikido" on his own.
"Ki," and indeed "aiki" may each in my view, be used to wield either a life-giving sword or a life-taking one, albeit with different consequences for the wielder himself.
In my view, the difference may lie more in the difference between
"jutsu" and "do," not "ki" or "aiki."
And, since I'm taking this long, I'll close by remarking that due to the inaccessibility of Ueshiba's religious beliefs, making aikido a "path" is problematic. The vessel is there, but what to fill it with?