A general theme for my team is that time tracking is too complicated. Because users have so many tasks, their timesheets are too big. Sure we could reduce the number of tasks, but teams like the list of work items but shouldn't have to put 15 minutes to each sub task. The idea would be to select the tasks or parent tasks to show on the timesheet.
Time tracking at the project level is too high, while the task level is too low. If we could log time at the parent task level or task level if no parent exists, then it would greatly simply time entry.
An alternative is update the timesheet view to show the Parent Task above tasks, then allow for hiding the children tasks. Then people would just see and track time to the parent tasks.