Greg - I appreciate your input, even if it wanders a bit. So it appears you are using SharePoint 2013. Is there anyone who is using Performance Point with SharePoint 2010? And what database edition are you using for the Analytic Server? All I know so far is SQL Standard 2008 is not recommended for Performance Point. Did you put SSAS on the same database server as SharePoint Database, or a different server? And, how was performance and response time? Again Thanks. :-)
Part of the rambling was to try and give you a overview.
This would be more important in understanding where things are headed when you upgrade.
Licensing is also a big part.
We had SQL Enterprise, not because it was required, but for the specific features.
Data Driven Subscriptions and being able to partition our SSAS cube were very important.
PowerPivot (tabular SSAS) I think might require Enterprise, but this is completely separate from the your demo description. Be sure to check this for SQL 2012, as it may be different than SQL 2010.
I would stand a cube up on Std, and then see if you get good performance you expect.
Much can depend on both the volume of data, and what is available in the cube.
Note that partitioning by Date is real common in SSAS, for both query performance and loading data / processing the cube. Note that you can have a Dimension by Year, but not be partitioned on the back end by year.
PowerPivot as an Excel Add In, can be used without SharePoint on Excel 2010 or up.
Which actually might be a good platform to prototype with first.