Hi Mike, thanks for sharing this good idea! These things must always be weighed up against the more clutter/complexity it produces – even though this might be a very simple and efficient way of planning lip-sync. I will definitely think deeper about it! Thank you!
Playing devils advocate: How would it work for you, if you just quickly drew simplified mouth shapes in the annotations column? It would be the same, if I’m not mistaken – even though your way might be slightly faster. But depending on the character design, the generic mouth shapes you are suggesting, could be fairly far from your actual characters mouth look, so you would run the risk of it being not precise enough and slightly confusing. I may we wrong of course. And you probably already tried this and came up with your idea.
Let me know what you think? I love to think about these things! It’s great. 🙂