nono, the size is fine. In fact, much smaller and it would be hard to view.
I like it a lot. I would maybe have tried to fill the frame with chairs instead of leaving an open space in the bottom right corner. Other than that, very good!
I wasn't happy with the chair backs either but i was at the rear of that section of seating. Really wanted to get a picture from the front row looking up, but lots of people around spoiling the composition.