DC's grittier, more realistic approach is going to sell. There's ample evidence for that already with the success of the Nolan trilogy, to some extent the darker and more serious themes of Winter Soldier (and Civil War), and Netflix' Daredevil TV series.
The approach just jarred a lot of traditional Superman fans that hold the Donner/Reeve conception of the character dear to their hearts--they were like WTF??!!!. With MoS they weren't expecting an approach to the character that is by comparison far closer to Watchmen, let's say, than Superman: The Movie.
But DC's superheroes are in a lot of ways more reminiscent of the pantheon of ancient Greek gods than Marvel's superheroes. (Which if you go to the ancient source material is hella dark!) So WB has a lead director, and chief architect for the DCEU master plan, that delves into that dimension by playing it up, giving us more intricate worldbuilding, and framing the tales as if they actually existed in our real world. These films will be action packed, a visual feast for the eyes, heart-pounding, thrilling, and 'majestic' or epic feeling--that goes without saying. But like Tolkien's Middle-Earth or Watchmen they're also going to have lots of layers to peel back about mythology and what these heroes mean to the collective cultural psyche, and so forth. That will subtly and skillfully be embedded for those who love to find such hidden treasures in this genre.
That is WB's big gamble. But I think the stylistic approach is going to ultimately sell. As much popcorn fun as the movies are surely going to be, they are at the same time going to take a serious dramatic approach to the superhero genre.
I watched an interview once with Snyder where he laughed that he made Watchmen because in his mind it's a serious source book, which he more or less faithfully translated as an art film, that 'legitimizes' his love of comic books. Zack is all into Joseph Campbell and whatnot and "the why of it" with respect to the films iconography. But he is amazingly subtle, actually, at weaving those more conceptual layers layers into the film, which first and foremost is an escapist entertainment product.
Anyway, WB decided that's where they are headed with the DCEU. There is a huge market for grittier, darker, and more realistic superhero films--that is already established. So they are following that direction. And again, admittedly, MoS launched that approach somewhat fitfully and shockingly. But as noted that was mainly because fans had so much cognitive dissonance with such an approach in relation to the Superman character specifically. With the Batman and Wonder Woman characters it will feel far more congruent. BvS will make it clear that the more mature approach will work fine for the JL (of which Superman is a part).