Hey, whatever gets kids reading. Or anyone, for that matter.
As for the entire thought of lack of originality, I'm thoroughly enjoying Brent Weeks' Black Prism right now. There is, of course, an unremarkable teenage boy who is becoming quite remarkable. Or so it seems. I'm not done yet. I suppose he may end up average. But I doubt it. The last Weeks series I read also had an unremarkable young boy who becomes remarkable.
If I started to count the number of books I've read and enjoyed that include a protagonist who begins the story unremarkable--and ends up remarkable--I think I'd these books would make up the vast majority.
I tend to agree with the poster who said earlier that readers simply like these story-lines.
Now, it's true that some authors invent fresher concepts than others. It's really up to the reader to decide if the "fresh" is acceptable to the palate. For authors like Weeks and Sanderson, for example, the reader must understand, accept, and enjoy magic systems. 10 years ago it wouldn't have kept my interest. Now I love it.
Different strokes for different folks.