Firstly: what a great blog post! Links to videos, nice headers, in-depth thought, references. Really nice. I liked the quote by Albert Einstein at the beginning; I completely agree that learning is most effective through experience, that is always when new information sticks best. After all, experiential learning is how we all learn naturally, as explained in the second video shared!
Focusing a blog post on interactive learning design is a great idea; I think finding engagement in course material is key to learning success, and is often hard to achieve with course material that is not naturally interesting to the learner. The lego tower idea is GREAT! And I wish I got to use something physical, like lego, when learning subtraction 18 years ago. Math is one of those things that seems easier to understand when you can visualize what the numbers represent. I think your subtraction lesson will work wonderfully!