Here we use quite standard templates for our tasks in 4 weekly cycle, so copying a task and changing the dates is quite useful to us. The option to add a number of days to a task and subtasks would be really helpful rather than manually inputting the date each time.
For example Task A is on the 8/06/18 but I would like to add 28 days to that making it the 06/07/18
Hope this makes sense