I'd love to see more granular insights/correlations between activities and sleep/recovery. As an example, what if instead/in addition to it showing that Mindfulness increased Sleep by 5%, it could say "On days that you've logged a Mindfulness Session, your Deep Sleep improved by 5%" perhaps with a graph of your daily deep sleep and it highlighting the days when you logged a Mindfulness session.
That's just an example, but the need is that there are certain metrics that I want to improve (HRV, Deep Sleep, etc.), and it would be more helpful if insights could tell me how my actions contribute to those metrics.