The problem with ki isn't that it's in another language. Kotegaeshi is in another language. The problem with ki is that it's a vague, mysterious word with no agreed-upon definition that is used to explain things that don't need explaining.
I can get that you don't like the ki model or whatever, but to say that it doesn't need explaining? Really? There are plenty of examples, both in and out of martial arts, where mental visualizations produce physical results. Whether it's someone visualizing water flowing from their arm which makes it harder for someone to bend, a guy taking a cannonball to the gut while visualizing a furnace and bellows in his stomach or someone lifting an object off another person in an emergency that they couldn't budge in any other situation, the mind plays an interesting and not completely understood role in the coordination of the bodies systems. That we can, to some degree, condition and train this and have it produce physical results is pretty interesting stuff to me, regardless of whether or not I know exactly how it works. I don't think ki/chi/intent/etc are attempts to explain why this thing happens, it's just a way to get someone else to feel it too and at that point why is still interesting, but not entirely needed.