Yeah, an Open-World expansion like Makeb and Yavin will keep the players busy for longer. KOTFE and KOTET were so linear... You cant run around and explore and its the same everytime you play it. On planet expansion we have new achievements, reputations, WBs , etc.
We dont need new planets with each new expansion! Make a new sections on the old planets like Tatooine, Alderaan, etc.