I think you misunderstand me. I'm not saying that these things don't need to be explained at all. I'm saying that what we know of science explains them without resort to a belief in ki. It absolutely is interesting stuff, amazing stuff, and I think it is a privilege to study it and practice it.
Even though this kind of use of the word ki is certainly a lesser offense than talking about mysterious supernatural forces, I still think it unnecessarily muddies the water. In the training I've done with Ikeda Shihan, he's always been able to convey that feeling you're talking about without falling back on so vague a word as ki, and his English isn't nearly as good as ours. If he doesn't need ki to explain himself, then I don't see how any of us do.
Except that science doesn't explain it, not the how and why.
and I disagree completely about Ikeda sensei. I've been to his seminars and I enjoyed it, he has strong aikido, but the one thing that disappointed me was his inability to explain what he wanted people to do without using vague feelings. How is "move inside" any better than "extend ki" or "bring chi here"? At the seminar I attended there was only one of his students there who could replicate what he was doing to any degree, physically, and that student is involved in outside training that revolves around the ki/chi/intent model. Nobody else (of his students) could do what he was doing, most had no clue what he was even asking of them and the few that seemed to have a grasp of it weren't given anything to work on outside of doing techniques to help them develop that grasp into something physical.
IMO the chi/intent model could have filled in that gap for them and as esoteric as it may seem on the surface, with practice and conditioning could have produced physical connection in them that they could use to make sense out of what he does. It's only mystical until you can produce something physical with those visualizations. I no longer subscribe to any other version of ki.