I doubt that many people are using the Oracle features "Rules Manager" and "Expression Filter" as usually people handle these things (such as ensuring that a zip code or a car number plate has a certain format) within the application code and not inside the database. Oracle Beehive for instance uses that just on the side. 

Anyway, just learned today that Rules Manager and Expression Filter components will get removed once our next database release most likely called Oracle Database 12c will get released. So before upgrading to Oracle Database 12c you can remove EXF and RUL components (SELECT COMP_ID FROM DBA_REGISTRY WHERE COMP_ID IN ('EXF','RUL'); ).

You'd simply do that by executing the following script before upgrade:
SQL> @?/rdbms/admin/catnoexf.sql
This will clean up Rules Manager and Expression Filter components inside the database. You could run ?/rdbms/admin/catnorul.sql before but I believe catnoexf.sql will clean up everything already.

And you'll find all this information plus guidelines for migration of existing content in MOS Note: 1233535.1 - Obsolescence Notice: Rules Manager and Expression Filter Features of Oracle Database

-M.