I think it would be helpful if an instructor could change an assignment marked late to on time or be able to edit the overdue timing right from the speed grader. How many times have we had students that just barely miss the deadline and you don't really want to apply the late penalty. It's a waste of time to back out to the grade book to make this change and then return to speed grader. Even if you want to let that penalty stand, if you had students resubmitting assignments for regrades or revisions, they will probably be flagged as late, even if they are submitted before an agreed upon due date.
Basically, I think that being able to change the status for an assignment from "late" to "on time" or "excused" just as you can in the grade book would be useful.