For what it is worth the Q-Trial did give an overall theme and arc for the entire series.
I never noticed it before, but even though there's no hint beforehand that he cares about humanity, there are several times at the end where Q actually seems to help Picard out
Such as when Picard is about to fire on the alien ship, and Q jumps in to criticize the idea. Or when he continually hints that there is more to the alien ship than appears on the surface.
All Q had to do was shut up, and his point would have most likely been proven for him. Lol