No more OWC-based PivotCharts, PivotTables, Trend Charts and Excel Spreadsheets. Good.
ASP.NET Dashboard Preview Site
One of my favorite features of PPS 2007 is now gone. Because the storage and management of elements are now almost entirely MOSS based you will need a complete installation of MOSS 2010 to be able to play with the new stuff. The silver lining here is that MOSS 2010 will be supported in a Developer configuration on Vista and Win7 PCs. So now developers will be able run their own sandbox environment locally.
Support for SSAS 2000 databases
Anyone who still has an SSAS 2000 DB running in production ought to be ashamed of themselves.
ODBC Tabular Data Sources
ODBC data sources were a rarely used feature of PPS 2007, and BSM for that matter. Although you could connect to just about any data source you wanted to, you could only bring return a scalar value per data source element which made these data source types tedious and of little real value.
32 bit Architecture
Because PPS is now part of the MOSS 2010 furniture it goes without saying that it only supported on 64 bit platforms. Hello better scalability.