I honestly already feel like I know what's going to happen:
Cavill will be all right, but will be hurt by the reduced screen-time.
Affleck will kill it, even if I'm not generally a fan of the Miller Batman.
Eisenberg will either be okay or very good in his role, but that version of Lex will be so different from the businessman/Clancy Brown version that people will shit all over him anyway, even though Heath Ledger was a pretty different Joker.
Gadot will do some cool shit, but we won't see enough of her dialogue wise to know if she can carry the role.
The story itself will have massive amounts of PIS to get the two men to fight, and they'll probably become friends just as easily as they started fighting. There'll be twists/reveals that involve Apokolips, and far too much will be crammed in to the movie.
There'll be good and bad, but people are going to complain not just about the bad parts, but the parts that are just different to what they wanted from it.
Like I will with Momoa.
I'll see how right or wrong I am come Thursday night.