A fundamental part in geometry is the ability to write and use proofs to support your work. Khan Academy has recognized this by making video proofs of certain theorems (ex: proving the Law of Sines, proving opposite sides of a parallelogram is congruent, etc.)

However, I suggest there be a section at the start under "Geometry Foundations" talking about proofs in general. For example, three types of proofs I have come across is Two-Column Proofs, Paragraph Proofs, and flow proofs. Two-Column Proofs have been shown across some of the videos but there has been a lack of explanation regarding writing them. 

Under this new section, one video could be "What are Proofs?", another could be "Writing Paragraph Proofs" or "Writing Two-Column Proofs". Also, another video could be "Coming up with reasons to use justifying in proofs". Videos under this new section would give learners a better appreciation for geometry and proofs. This, in turn, could help students under what geometry is all about, because geometry isn't about just "shapes". There is much more to geometry then that.