You could go the distance and have the ability to toggle anything on/off while recording, and viewing replays.
For recording, we should also be able to toggle parts of the HUD, e.g. hotbar, life bar, armor bar, water bar, object in hand etc.
When in View mode, this information should be available when we're spectating players/entities, so it's easy to tell if the entity is getting damaged.
Would be useful.
Nope.