A Star Wars themed park wouldn't work for different reasons in my opinion. More people than you think go to Disney World or Disney Land because they want to see Disney stuff.
A Star Wars park sounds to me like early California Adventures. John Lasseter said it himself: DCA's problem is that it didn't have enough Disney in it, even having a strong theme and great attractions.
Point is, everyone can relate to at least a few Disney characters, but not everyone knows what Star Wars is all about, especially since its popularity peak was a long time ago.
Disney content doesnt make a Disney park. In fact, its been quite the opposite over the years. Throughout the 70s and 80s the attractions in the Magic Kingdom had very little to do with any of Disneys intellectual property. Space Mountain, If You Had Wings, CircleVision 360, Mission to Mars, Star Jets, WEDway People Mover, Haunted Mansion, Hall of Presidents, Jungle Cruise, Pirates of the Caribbean and Country Bear Jamboree just to name a few. When Epcot opened I dont recall any Disney content being there. Animal Kingdom was overwhelmingly non-Disney and Disney-MGM Studios, while having a lot of Disney content, didn't rely solely on that material. Disney climbed to the top of the theme park world by being creative and engaging their customer base.
With respect to Mr. Lasseter, its not that DCA didnt have enough Disney in it, its because the park lacked that creativity and imagination that Disney was known for. They (Disney) has proven that they can still produce solid, creative products with Cars Land, and they can do the same with Star Wars. I hope they take advantage of their imagineering talent.