I would expect all of the analysis could be in pivots as you say. Pivots are more the analyst's tool, a laid out report (aka the cube functions) is more for the manager (don't expect them to do any looking ).

An example of how MDX can help is if you get a set of years from the calendar. You might use the following CUBESET function

=CUBESET("ThisWorkbookDataModel","[Dates].[CalendarYear].[All].Children)","Years")

This is fine, but it will bring back all years in your calendar. You would then list the years and show the sales for those years (using CUBEVALUE). But some of the years may not have any sales so the row would be blank. You can get a set of only the years that have sales using the MDX NonEmpty clause,

=CUBESET("ThisWorkbookDataModel","NonEmpty([Dates].[CalendarYear].[All].Children,[Measures].[TotalSales])","Years")

A very simple, but effective example I believe.