I agree, this would be especially useful for mega processes or processes that have a long due date, you don't want to get to the due date and find out only one activity has been completed
To add to this, if this feature is brought in then would like have any date changes made to an activity automatically update the same timeframe for subsequent set activities in the process. i.e if activity 2 in a process is given a 1 day extension, then all subsequent activities automatically get a 1 day extension.