You don't need to see Batman V Superman: Dawn of Justice. It's bad. It's a bad movie because it's a bad interpretation of pre-existing characters.
It's so bad that people have taken it personally. I've written in the past (yesterday) concerning the lengths people will go to preserve their baby-brains, to remain psychologically childish, rather than develop into a forward-thinking headspace. Batman V Superman is an example of denial that certain comic book fans live and die by.
Fans see their favorite characters alive and human-shaped on the screen in movies like BvS. They take that as gospel. The sight is all they require. I'll stay to my orginal point that BvS was a bad movie because it's a bad interpretation of characters the audience is familar with.
Batman and Superman.
I'm not going to dissect just BvS here though. I'm going to do a spot-check on how well DC is constructing the shared universe for their movies.