This is really cool, looks good, and I love the idea.
I understand the amount of time required in adding quality content, but as somehow who is more into training, those are the features I think will take it to the next level:
1. breaking down muscle groups or at least adding information for the videos of what exactly it's working on (especially for posterior/medial/anterior deltoids, abs breakdown).
2. Adding muscles - especially obliques, maybe also serratus.
3. Adding info for videos which other muscles it targets, dos and don'ts, and optional progressions/regressions.