When you only use one level, it will give sentiment by index of each level, rather than the level as a whole - this makes it hard to read the actual sentiment, and I think is a bug. Using more than two levels doesn't have a bug like that, but it does look messy. It also might be nice to see the average sentiment of the main level across time periods (right now it just shows the divisions - so if you had North America as one level, its countries as another, and its time periods, you would just see sentiment for each country, not NA as a whole). Not sure how possible or useful that would be, but is something I noticed.
When you only use one level, it will give sentiment by index of each level, rather than the level as a whole - this makes it hard to read the actual sentiment, and I think is a bug. Using more than two levels doesn't have a bug like that, but it does look messy. It also might be nice to see the average sentiment of the main level across time periods (right now it just shows the divisions - so if you had North America as one level, its countries as another, and its time periods, you would just see sentiment for each country, not NA as a whole). Not sure how possible or useful that would be, but is something I noticed.