If there was one thing interesting about The Force Awakens teaser was what it didn’t reveal. Or more specifically, it didn’t reveal anything that wasn’t already known in one way or another. Spoiler-hounds recognized almost everything in the teaser as Lucasfilm was very careful to not show anything that hasn’t already been leaked in one way or another.
It turns out this may be deliberate, as according to a Twitter insider (who has leaked some marketing material in the past) the leaks of concept art from The Force Awakens has affected how Disney is revealing things:
One big rumor is that we didn’t see Kylo Ren’s face in the trailer because of all of the concept art leaks and descriptions of what his helmet looks like. After the teaser was released, concept art came out to show people what they were missing.