Sims 4 Island Paradise: Expansion or Game Pack?

It would have to be expansion. Would need a decent size world in order to really swim in oceans and scuba dive, houseboats, etc.... People been wanting mermaids and other things again. It would be too much for a game pack as the game pack won't be able to give us everything.

There would be new recipes, activities,careers, traits, skills, etc.....so much can be added.