Agreed. A high profile actor can help build awareness for movies that usually don't get the attention but for blockbusters, it's the subject and the appeal of the story that matters much more.
I'll believe it when i see it. Ridley is attached to so many other projects right now and he isn't getting younger. I hope he doesn't waste too much of his time with stuff other than sci-fi, just because i'm a fan of the genre.