I think the biggest problem is that DC saw what Marvel was doing and wanted to emulate it while simultaneously trying to be the polar opposite. Where Marvel went with the lighter, more jokey tone, DC went for more dour and gritty. They saw the success that Christopher Nolan brought to the Dark Knight trilogy and wanted to emulate that without realizing that such a tone fit for Batman but had no place with Superman or any other DC hero.
Yet, it worked quite well with Wonder Woman, which came closest to emulating the MCU feel.
They should've done Wonder Woman before Batman V Superman, and done a new Batman movie before Batman V Superman.
Not to mention the former makes Batman look like an overtly hostile douchebag.