There are features in the legacy version that are not in version 10. They are simple things and so I don't know why they haven't been implemented until today. These are things that are needed in daily use. I will only mention two but I believe there are others, so anyone who remembers others is free to speak.
1 - Put colors in notebooks and labels. "Style" option
2 - In the list of notes in the Side List view Possibility to classify notes by Location, Tags and Size. In version 10 it is not possible to do this.
Note: I don't speak English so forgive me for any errors in writing.