Disney CEO Bob Iger says that J.J. Abrams didn't want to release any footage at all and was so obsessed with retaining the mystery behind the film that he had to be convinced that releasing the teaser was the right thing to do.
Iger was convinced it was due to the rabid Star Wars fanbase and revealed to Variety this week: "I keep telling J.J. Abrams this is a $4 billion movie. We need to treat this very special. It's an unbelievable privilege and unbelievable responsibility to take a jewel, and treat it in a way that is respectful of its past, but brings it into the future."
Iger also says the aim with the film isn't to go big with massive spectacle, but rather trying to using less CG and more practical effects where possible: "[The] wow factor isn't what it used to be. The film [will have] a look that will be extremely respectful of the look George [Lucas] created in the '70s."