I believe that this setting is held in memory so we currently don't have a way to configure Workbench that would make the preferred sorting order on the packages tab persist from one Workbench session to the next. Have you thought of posting this as an idea?
We can't change the default configuration on the Packages tab, but what we could do is create a BIRT report that will present the list of packages sorted according to your preference. Here is an example that would work at the state level:
SELECT HARPACKAGE.PACKAGENAME,
HARENVIRONMENT.ENVIRONMENTNAME,
HARSTATE.STATENAME,
ASSIGNEDTO.USERNAME AS ASSIGNEE,
CREATEDBY.USERNAME AS CREATOR,
HARPACKAGE.CREATIONTIME,
MODIFIEDBY.USERNAME AS MODIFIER,
HARPACKAGE.MODIFIEDTIME,
HARENVIRONMENT.ENVOBJID,
HARSTATE.STATEOBJID
FROM HARENVIRONMENT
INNER JOIN HARSTATE ON HARENVIRONMENT.ENVOBJID = HARSTATE.ENVOBJID
INNER JOIN HARPACKAGE ON HARSTATE.STATEOBJID = HARPACKAGE.STATEOBJID
INNER JOIN HARALLUSERS CREATEDBY ON CREATEDBY.USROBJID = HARPACKAGE.CREATORID
INNER JOIN HARALLUSERS MODIFIEDBY ON MODIFIEDBY.USROBJID = HARPACKAGE.MODIFIERID
INNER JOIN HARALLUSERS ASSIGNEDTO ON ASSIGNEDTO.USROBJID = HARPACKAGE.ASSIGNEEID
WHERE HARENVIRONMENT.ENVOBJID = ${PROJECT_ID}
AND HARSTATE.STATEOBJID = ${STATE_ID}
ORDER BY HARPACKAGE.MODIFIEDTIME, HARPACKAGE.PACKAGENAME
Let me know if this is the information you needed.