Well, you know that JJ wants to establish his rep as an action director AND as an auteur as Spielberg did early on. JJ thought he was going to do that with Super 8. Didn't quite work out that way. Whereas Spielberg hit the jackpot with Jaws. Seeing that JJ has reformatted the Khan character into something more complex and more akin to what he was in TOS (as you shrewdly upthread observed), Cumberbatch's range as an actor allows JJ to do many things. Let's see what happens.