He's arguably the coolest character in the show. A giant flying lion, emperor of an arctic kingdom full of sentient automatons, named for a giant celestial object going 2,288 MPH. The fascination abounds.
And he only gets one scene. In the play, they had to make this big (presumably expensive) puppet for him, and he has two or three lines, never seen again. What's the deal? Where did this guy come from? Who thought of him? When they were writing this script, how did the character come about? Did he have a larger part that got condensed? Are there more flying lions in this world? Why is he called Moonracer? Does he have some kind of relationship with Santa Claus? Possibly rooted in the same mythos?
He's got a whole throne room and guest quarters, but his palace as empty as a politician's heart (politicians are such easy targets). But he also has a job -- taking toys that are no longer loved and bringing them back to the island until a child loves them. First, how does King Moonracer measure this? Is there a test the toy has to fill out? This isn't like adoption, it's closer to kidnapping.
Second, this is a zero sum game. How many toys have you lost or given away or trashed that found another home? That population is on its way to surplussing in no time. King Moonracer is a hoarder. Or he would be if he hadn't asked Santa to get rid of his trash for him. Oops, I mean, find loving homes for the f#%$ed up toys. You do know they're just a degree outside Sid's creations, right?