I watched this cartoon as a kid, and a lot more now that Boomerang is showing it. It's another one of the Hanna-Barbera formulas where a zoo-keeper or similar is trying to keep an animal from getting into mischief. These would also include The Hair Bear Bunch, Squiddly Diddly, Magilla Gorilla, Yogi Bear, and I'm sure a few others that aren't coming to mind. This is what I would consider good Hanna-Barbera, where I'd put Yogi, Huckleberry Hound, and Quickdraw McGraw as the best. I at least like this formula better than the group of teens solving a mystery formula, which was WAY overdone after Scooby-Doo, and with little talent. The one thing I don't get about Wally Gator is that the opening theme has him riding a boat around a swamp, while the theme song says "Wally Gator is the greatest operator in the swamp." The show takes place at a zoo though, there is no swamp there. There's one episode where he breaks out of the zoo and returns to the swamp to steal turnips from a farmer, which he says he used to do when he lived in the swamp. So maybe he was once there, but not in the show. You could wonder why the greatest operator in the swamp would allow himself to be captured and put in a zoo, but then he does mention how zoo life is much more luxurious, meals brought to you, etc... so maybe its exactly what he wanted.
