"Drop lowest score" is too limited to be useful.  For example, my course works on total points, and I have assignments ranging from 5 to 100 points in the gradebook.  Right now, "Drop lowest grade" could mean one student getting a 5 point assignment dropped, and another getting a 100 point assignment dropped.

It would be helpful if we could set a maximum amount of points or maximum value of an assignment that can be dropped, rather than having to pick every assignment that should be ignored.  Since dropping the lowest score typically happens at the end of a semester, it makes for a lot of work to have to manually go through a gradebook and choose every assignment to exclude.