This is pretty cool on the part of the producers. Maybe my dreams will finally come true and one of my screenplays will become an actual episode! (At least, I can dream about it.)
Have they ever done an episode where one of the kids develops a crush on an older person? I know it's been done to death on kiddy shows, but I can see a scenario where Lakewood hires a pretty, nice, makes learning fun, new teacher (probably just a substitute teacher), whom Arthur, or one of the other boys (maybe Buster perhaps) develops a massive crush on.
They did this in season 6, the episode was "Crushed." Arthur had a crush on his babysitter, but they really beat around the bush with the idea that he had a crush on her, and it was more implied than anything. I think it could do with a revisit.