Please be advised: There are spoilers ahead for Frank Miller's The Dark Knight Returns' graphic novel and animated film.
As we know, Batman will be fighting Superman using a mech-suit.
And he will be an older, more jaded and world-weary Batman.
Although this is a guess, it looks like Batman will use the same rifle featured in TDKR that he uses to cross between buildings via a tightrope line or zipline.
And also speculation, but the BvS's Batmobile equipped with machine guns probably uses the rubber bullets per TDKR
TDKR has Superman intercept a Russian nuclear missile that is headed for the U.S. It looks like the BvS trailer features what may be a variation on that theme. In the trailer it looks more like the rescue of a failed launch of a rocket. (Perhaps a manned space capsule versus a nuke? Hard to say at this point.)
Addendum: Actually, looking at the nose of this thing I doubt it is a manned space capsule:
Anyway, as mentioned, it is clear that Batman v Superman will be selective about what it uses from TDKR and that it will be a unique tale in its own right. But it is hard to overlook that the Joker plays a prominent role in TDKR. In TDKR Batman ends up pursuing the Joker through an amusement park for an epic final showdown with the Clown Prince of Crime.
In my opinion Jared Leto's portrayal of the Joker in the Suicide Squad trailer bears a strong resemblance to TDKR's Joker (to my ear Leto's Joker's voice also sounds quite a bit like TDKR's Joker).
(Note: It seems that The Killing Joke's Joker is also a source of inspiration for Leto--certainly the eyes are.
But the Joker's hair there is a dark green and curly.)
In the Suicide Squad trailer, we don't know yet who is behind this robbery but the masks they use is reminiscent of TDKR's Joker's use of a mask initially at the amusement park. This motif certainly has a Joker-like flavor. It may just be a coincidence, but it is interesting to note.
And of course in the BvS trailer we see Bruce Wayne/Batman having been taunted with the graffiti on Jason Todd's charred suit; with similar taunting from someone continuing via the newspaper note--and this certainly has the Joker's style all over it.
Now the main reason I am leery that the Joker will appear in BvS is that in TDKR it ends with the Joker's death! And if that is followed that would obviously make no sense whatsoever for Suicide Squad, since the Joker is clearly alive and well there (unless the story is set prior to BvS). I also think that it may be a bit too soon for the Joker to appear in a Batman film. But then again, BvS is using TDKR loosely for inspiration and by no means following it to the letter. So the Joker could appear as a villain in BvS, but not die as he does in TDKR.
Also, there could also be some groundwork being laid here for the arch villains that the Justice League will face again later down the road, for the JL films to come. Lex Luthor and the Joker are the number one nemeses of Superman and Batman, respectively. So it does kind of make sense to also introduce those two villains in the DCEU's first film to initially bring the core trinity of the JL together.
Anyway, what do you think? Have we too easily dismissed the Joker as the other main villain that Batman and Superman face in DoJ?