I like the star ratings. I think they're good as a rough way of marking how 'good' days were as a whole. I see a 1 star as a terrible day, 3 star as normal, and a 5 star as a peak experience and use these on my day log entries. Come to think of it, is there a way to show all entries of a particular rating?
I also get it that stars do not encompass the depth of feeling so feel emojis could be a good idea in addition to the stars as a sort of mood tracker. In which case, I think it would be good to allow the range of emojis with a previously picked selection for people to add to their entries easily.
I noticed that you can tag entries with emojis already, but I can't think of anywhere else in the app where they could be useful.