George S. Ledyard
The Systema guys don't look like any martial art I have seen anywhere despite the fact that I think you are right that the internal skill development is the same.
Just to be clear about good hitting with a fist, for example. I've been hit by a lot of boxers, even one heavyweight contender. They can hit amazingly hard, even when they "do it lightly". But they've practiced hitting so long that certain basic elements of a good hit, such as including the body mass in the hit, show up in many of the practitioners' hits. It's ONE of the same major components of internal skills, although it's not all of them. But that being said, the major demonstrations of good "internal" skills are based on the refinements and permutations of only one or two core principles.