I have one suggestion regarding the first for a more efficient way of teaching I have been taught. At the first video, the success ratio is around 5-10%, most people do not learn this way, at least not efficiently. The way I am taught, you should have lowered the requirements at that point (best solution -- both move slower).
As for the second video, the success rate is around the efficient area. Yet, a teacher would have probably pointed out to you, you are still late in your Irimi, even though the technique is working (I can say this with ease since I have the same problem).
Only yesterday we did a similar practice, with Tori learning to blend and Uke attacking freely (for us veterans this included all kicks too). And, Sensei has instructed my Uke to slow down, since as our speed grew I became "jumpy", "too on edge", lost the smoothness of the movement, and mot importantly, Sensei could see I was stopping to learn and starting to "fight".
As I said earlier, I find nothing wrong with the ideas behind the exercises in the videos. These ideas with similar exercises actually exist as in integral part of our curriculum. Because of the that, we do those things as part of a well defined methodical approach, and the teacher is not experimenting, and knows the exact purpose of each exercise he gives, which exercises we should do in order to improve specific traits, and what changes and comments are relevant to each.