To give you all a better idea of Makeb's scope, it's a planet of equal size to our larger planets and it contains a variety of areas – sprawling mesas, underground caverns, garden estates, and more. It introduces faction-specific storylines, new Heroic missions and bosses, repeatable mission series, and new Datacrons! The 5 new levels will occupy players for a fair amount of time, and there's plenty of content to get you there (including a lot of stuff tucked away for the explorers out there). Keep in mind that this announcement is just the start – as we approach Makeb's launch, you'll see more details about the content coming with Rise of the Hutt Cartel!
Sorry but this is not an expansion. This game is not set up to allow for a true
expansion. You'll never be able to continue the players storyline since you'll never be able to afford the voice actors again.