It would be nice to make some global dynamic data selection rules on the source. E.G. the BUKRS field in SAP appears in many tables to indicate a company code. A user would then be able to create a global rule that would do something like "if you run into BUKRS in any table always apply data selection rule BUKRS=XXX". Or if this rule is in effect tx would automatically add it to a newly added table.
For SAP development this shaves off a lot of repetitive tasks :-)