You can add to the tracker as a feature request or join Moodle User's Association and try it there - not sure how much interest there would be but I could how it could be useful...
I also want to how many student I can enroll to particular course,actually I am facing the issue that after enrolling 'n' no of user to a course,my course hangs out nothing gets open not quiz not content from that course.
So I want to increase course capacity for student.
Thanks Emma. I just added a feature request at https://tracker.moodle.org/browse/MDL-57164.