I really like the idea of your videos, but the important question would be: who is your target audience?
If it is young students who are not familiar with VEX yet, then I feel there are some portions of the video that are a bit too heavy on the theory and might be not as easy for the students to follow. For example, when you talk about gear ratios at 4:30, I would love to see a gearbox with gears that you spin by hand and later a long geartrain that would illustrate how chain is better to transmit power over the longer distances.
On the other hand, if the target audience is older students who are experienced with competing with VEX, then they may find some examples not applicable to VRC. For example, you say that “most of the times you want to drive your traction wheels and let omni wheels to spin freely” at 3:10:
However, that choice depends on the surface on which you intend to drive your robot.
On the foam tiles for VRC fields omni wheels offer the best traction and most teams use chassis with four powered omni wheels.
Also, you may want to include some slides with mechanism sketches or diagrams, in addition to narration, to make material easy to understand both for visual and auditory learners.