Wait, hold on. McGrew's Zoo isn't boring. Did you see that place? It was off the awesome chart.
We agree with you, but If I Ran the Zoo doesn't take place in McGrew's Zoo. That place is a figment of his imagination. If you want to talk about that zoo, you'll need to jump over to our "Symbols, Imagery, Allegory" section. The book actually takes place in the plain old boring zoo where McGrew starts all this creating and imagining.
Why is it important to consider the boring old zoo? If you check out our "Characters" section, you'll see our suggestions that maybe the zookeeper is the primer for McGrew's imagination. That is, when McGrew sees the zookeeper, he imagines what it would be like to take on that role. The plain old zoo contributes a similar primer for McGrew's zoo. McGrew takes the basic structure of the zoo and uses his imagination to build on it: tweaking this thing here, changing this thing there, and removing what he doesn't want.
The lions, elephants, and wildebeests are out, replaced with the likes of natches (28.1), proos (32.10), and a Fizza-ma-Wizza-ma-Dill (34.4). McGrew also imagines a totally different structure for the zoo. In the first drawing of the book, the boring real-life zoo is fairly typical, even boilerplate. There are animals, they are in cages, and a sign tells you what the animal is.
McGrew's fanciful zoo is an entirely different creation. The animals run wild amongst the visitors. While some are in cages, the cages seem more like homes than confinements as the creatures enter and exit the bars at their leisure. The zoo also features the only splash pictures in the whole book—that's what those in the biz call a drawing that crosses between both pages. As the people say, "What this zoo must be worth! / It's the gol-darndest zoo / On the face of the earth" (35.2-4).
Even though the zoo may not be as exciting or fanciful as McGrew's creation, it's still a very important part of the book. It shows us that even the most imaginative and creative thing in the world probably had very humble, very real, origins.