Currently, the donut chart is the only visual that contains a percentage of total label. If you have a lot of categories, a donut chart becomes less useful.
I know you can use a measure to achieve the same for some of the other charts, but you can't create measures in a SSAS live connection.
It would therefore be very useful if the percentage of total was added to (some of) the other visuals as a detail label option, especially in the bar chart ones. It seems like this would be a pretty straightforward edit, since it already exists in one of the standard visuals.