That's exactly how Warner Bros. intended it to be with all the hints and Easter eggs that they dropped, which they also knew would be nitpicked and theorized by today's blogosphere.
It has reached a point wherein there are already betting odds on which rumors will hold true. One rumor seems to have reached "inevitable" level, and that is the possible appearance of the Joker.
Cinema Blend has enumerated the hints on the trailer in this post and they reach a conclusion that all those Easter eggs-the damaged Robin costume and the vandalized headline, among others, lead to a clear conclusion.
"But with all of these hints dropped into this second trailer, I think it's extremely likely that we will see Jared Leto's Joker before he appears in Suicide Squad later next year."
What Culture also crashes the Joker party with a full-on prediction on how the appearance will take place.
The article also stated that the main argument against this rumor is that the film might already be "overstuffed." There are already a number of heroes to be introduced in the film to add the Joker to the head count.
The thing is, that is actually the intent of the movie. It has already been confirmed that BvS is more "Justice League" introduction and DC Extended Universe building block than "Man of Steel" sequel. It was meant to be that way, and the Joker plays an integral part of what makes the Ben Affleck Batman "scarred.