RE: Takes long time with F4 key on package or with schema browser when user tries to view package body from other schema.

There's nothing you can do in 12.1 to make that part of the query not run.

However, in our latest version 12.9, that query has been rewritten a bit.   If this runs faster for you, you might consider an upgrade.

with PACKAGES as
  (Select owner, object_name, object_type, decode(status, 'VALID', 'V', 'I') status, last_ddl_time, object_id, created
   from sys.all_objects
   where 1=1
   and object_type in ('PACKAGE', 'PACKAGE BODY')
   and owner = :own)
SELECT PACKAGES.owner, PACKAGES.object_name, PACKAGES.object_type, PACKAGES.status,
       PACKAGES.last_ddl_time, PACKAGES.object_id, PACKAGES.created
       ,NVL(pi.AUTHID, 'DEFINER') AUTHID
       ,NVL(d.debuginfo, 'F') DEBUGINFO
FROM   PACKAGES
       ,(SELECT   object_id, authid
         FROM     sys.ALL_PROCEDURES
         WHERE    subprogram_id = 0
         AND      object_type = 'PACKAGE'
         and owner = :own
         GROUP BY object_id, authid) pi
       , sys.all_probe_objects d
WHERE  PACKAGES.object_id = pi.object_id (+)
AND    d.object_id (+) = PACKAGES.object_id
AND    d.owner (+) = PACKAGES.owner
order by 3, 2