Well, it does depend on what your definition of a full day is. If you're only here for the rides, you might end up being disappointed (not in the quality, but the quantity). For example, Hollywood Studios is a half day park, Six Flags Magic Mountain is a full day park.
But, if you're here for the full package, this absolutely is the park. There's so much to do here, you got 12 rides (if that dome in the hub is a flat ride like I think it is), three built in shows, a parade, fireworks, and a ton of interactive experiences and play areas. Not to mention that two of the rides (AKA Mario Kart and the Fantastic Beasts shoot-em-up) are interactive, leading to tons of re-ridability. You can just relax and take in the atmosphere if you want. There's stuff to do in the rain. There's stuff to do if you don't want to ride anything. It's perfect in a way that no park in Florida outside of Magic Kingdom is.