With someone like Saotome Sensei, uke's balance is already gone by the time he actually touches nage. Which of course makes technique very easy.
It's possible to accomplish that without "internal" skills of any kind, through timing, body movement, etc. But it becomes more difficult the more skillful the attacker is.
I'm afraid you may be seeing what you want to see. Saotome Sensei does a variety of different things depending on what Uke does. The narration of his videos (if you watch them thoroughly) explains this most clearly. He explains this in his books. He talks about this at seminars, invitation only trainings, Etc. Saotome Sensei is not ambiguous in how he understands how Aikido works nor what he wants us to be doing as his students.
Sometimes it's internal. Sometimes it's external. Sometimes Uke is unbalanced immediately. Sometimes he's not. Sometimes there's resistance and then the question is how to blend with/use that resistance (the Oyo Henka video). Often Sensei moves behind Uke, Uke turns to pursue, and then Uke is unbalanced by his own following motion. There are even step by step examples of the roles of Uke and Nage in his book Principles of Aikido, complete with pictures. The most common movement that Saotome Sensei performs is the backwards tenkan plus weight shift. Again, not secretly internal, not only internal, and not ambiguous. He teaches the leading, blending, body positioning, concept of Aiki.