What a thread topic, try reading all of these articles:
The parameters for internal strength are discussed there much better than where this is all headed. Anyone with a teacher and a school is going to be miffed by not being acknowledged a having whatever it is. But these blogs have the reasoning laid out, and there is an unavoidable logic to the full body skill.
Dantien driven movement sounds nice and understandable but its a really extreme thing, and people moving like that have a very distinctive quality of movement and similarity of motions.
I have really seen no evidence at all that O Sensei did this, or that DR does it, or that anyone in Aikido does this.
But it is not the only way of using internal strength attributes; there are other ways. What is best? Ask Conan.