When the geometries are accessed directly from a spatial database then ArcGIS should automatically general the according SQL using appropriate SQL consctucts and SQL/MM functions in the database. A good example here is the spatial join that should be broken down to happen in database whenever possible, e.g. usong ST_INTERSECT or similar spatial join operators of the database. Today the user has to manually type up the SQL query in a query layer to leverage the potentials of spatial databases with ArcGIS.