Do I want to make a Star Wars movie? Yeah. I was like, “I don’t want to make a Star Wars movie. Like, god dammit, why?” But I saw the trailer for Rogue awhile ago and I was like, “I want to do that.” To make a Star Wars movie and not be wed to the bigger picture.
It sounds like the idea of working on a trilogy with others is not attractive but making his own self contained Star Wars film is. So far the company culture of Pixar, Marvel, and Lucasfilm hasn’t been one with too much cross-pollination (only Michael Arndt comes to mind on the film rock star level as he wrote Toy Story 3 and the initial work on The Force Awakens).
I’m in no way a detractor of Whedon’s but I’m not a rabid fan either. It would be interesting to see him make a Star Wars film but I would also rather see less defined up-and-comers continue to make the stand-alone Star Wars films.