Easy way to import public synonyms?

Instead of using export/import for re-creating your PUBLIC synonyms, why not simply reverse-engineer the DDL statements to create the PUBLIC synonyms and then run that DDL on the development database? The following SQL can be run on your production database.

SPOOL create_pub_syn.sql
SELECT 'CREATE PUBLIC SYNONYM '||synonym_name||
 ' FOR '||table_owner||'.'||table_name||';'
FROM dba_synonyms
WHERE owner='PUBLIC';
SPOOL OFF

The result will be a text file "create_pub_syn.sql" which contains all the CREATE PUBLIC SYNONYM commands you need to execute in your development environment. An alternative is to use the DBMS_METADATA.GET_DDL package to extract the same DDL commands, but the above works quite nicely too.