The easiest way to fix Casual = boring is to create activities that are just silly and stupid, in a good way. Take, for example, the Valentine event way. Building cakes while being chased by marmets.

They could expand/revamp the Gold Saucer since that already exists, and it's supposed to be a place for fun.

redesign existing modes + adding ones on top, and give each one of them also unique rewards on top of general ones.