There is a popular belief that Jesse Eisenberg was a bad Lex Luthor. There are 2 main reasons behind this and I can only get behind 1 reason.
The logical reason why people didn't like him as a Lex Luthor was because he they just didn't like him, they thought he was either cringy, annoying or just overly energetic for a dark tone movie and that broke the character for them. I can get behind that reason, it's matter of taste.
The nonsense reason why people didn't like him as Lex Luthor is because he didn't look or act like Lex Luthor from the comic books. Now there are 2 kind of people who support this decision. There are people who haven't seen the movie and are just jumping on the hatewagon, happens all the time. Secondly there are people who don't actually read comic books(though for some reason a lot of people want to pretend they do) and didn't pay attention to the movie or the news before the movie even came out.
Last year in 2015 we found out that Jesse Eisenberg is not playing Lex Luthor, he is instead playing Lex Luthor Jr. The son of the comic book Lex Luthor who created LexCorp.
Now in the movie J. E. talks about his father, how he created the company LexCorp and how his father was brought up in Germany(Metropolis in the comic books) by in slums by a poor family. That is literally the origin story for Comic Book Lex Luthor minus the Germany part. How people missed Jesse Eisnberg literally saying that is father created LexCorp and then laying out his origin story is beyond me.
Jesse Eisenberg was never supposed to be the cruel and serious Lex Luthor we know and love? from comic books. He was supposed to be modern billionaire like Mark Zuckerberg who he also acted as. Jesse Eisenberg in my personal opinion did a good job playing the role he was given, even if the role wasn't great. Well I think the role was great and Jesse playing it out was great as well.
Let's just forgive him that weird and out of place "Red Coats" reference that made absolutely no sense in the movie.
So let's remember now, Jesse Eisnberg was Lex Luthor Jr. not Lex Luthor.