Here's a quick question for you.
Harry took nine subjects at O.W.L. level, Hermione eleven (although the maths is iffy on that one), Percy and Bill got ten O.W.L.s apiece.
But what I want to know is how few OWL subjects you think a student could take? Would they, for instance, be allowed to drop all their elective subjects and leave them with the seven core subjects (DADA, Herbology, Charms, Potions, Astronomy, History of Magic, Transfiguration).
Or, if a student were spectacularly bad at a core subject, would they be allowed to drop it? I suspect not, but would be interested in your opinions.