I would LOVE to see Modified_by, Completed_by and/or “in tasks owned by” fields added to the advanced search. We employ tasks as templates, for onboarding and offboarding, which have hundreds of nested subtasks w/in them. To keep “My Tasks” clean for our users, we don’t assign sub tasks unless they are meant for someone other than the primary parent task owner.
When conducting status, I want to see what my employees have been working on, and how much they have completed for evaluation purposes as well as FTE output measurements. This is currently not possible as if I search for tasks assigned to an employee, completed within the last 2 weeks, I’ll only see the major parent tasks that are completed, but not the sub-criteria or any other tasks they may have been assigned or contributed to in recent history, as those won’t have assignments. Thus adding a modified_by field, would let me know if staff are commenting, completing, editing, tasks not assigned to them and completed_by, would let me see what sub-critiera within an onboarding, has been tended to.
By creating an option for “in tasks owned by,” similar to “in projects owned by” I believe could find completed, modified and commented tasks by date and resolve much of the criteria outline above.
Thanks! 
