Super Mario World? More like Super Mario Island. Because. Like, it's just on a single island. Do you think they regretted having already used this when they came up to Super Mario Odyssey which, like, actually involved a tour around the world. I would. Because it was a friggin' island. Not a world.
Look man. I know this is supposed to be a fun thread and all, we've had a lot of laughs, whatever. But it is
readily apparent that several of the locations of Dinosaur Land are not actually or not naturally connected.
You have to hop across another island to go from the Forest of Illusion to Chocolate Island. While the Cheese and Butter Bridges are atop a lake which connects Vanilla Dome to the east, Donut Plains and Yoshi's Island are only connected by a bridge which isn't even built until you beat Iggy Koopa. Until that point it's only connected by an ocean, and if you're going to say that's one island, you may as well say that North America and Africa are just one island. If anything it's an island chain, maybe a geopolitical region a la Oceania or Australasia.
While it is true to say that Dinosaur Land is not actually a world unto itself, the game makes no suggestion that it is anything other than a region of Mario's world. It also fits into the broader terminology of the Mario universe, where "world" is less used to refer to an individual planet, but moreso particular regions in which the overall gameplay area is divided. In that sense, Mario World actually contains multiple worlds if we follow the standard Mario lexicon.
Come on. It's just as easy to get these things right.