It would be nice to be able to see everything that was accomplished in the last day/2days/week/month/quarter.
An easier way to implement this would be to simply be able to order a list by "completed on" date which is already available data as we can see this when expending a completed task.
A better way to implement this would be to have dedicated view "Completed Tasks" (available under "My Day" for example) that would gather all the completed task from all the different lists and ideally allow us to customize the range (Ex. since X date or last X days)
