I mean, you'd lose most of the Appalachian Mountains which as one of the oldest mountain ranges in the world means losing a ton of ancient fossils that helped piece together the biological history of Earth. I'd also be curious how the glaciers would be impacted given how heavily they shaped much of North America

You also lose several major cities including Toronto and St Louis, Canada loses most of its habitable land (assuming the climate isn't significantly impacted by the existence of a second Mediterranean Sea, which it definitely would be) Chicago is going to be quite different but probably an even more important port city in such a world. Las Vegas is now a port city, so probably less casinos and more just major city. My wife would be sad because the Quad Cities (a metro area on the Iowa/Illinois border) wouldn't exist and she really likes that area. I'd be sad because the Mississippi River would be much short and therefore way less cool. But it's a really wild concept that gets crazier the more you think about it