Irons as Pennyworth? I can buy that. He seems a bit too aggressive for a role like this, but he is a tremendous actor despite his recent statements in interviews.
As for Eisenberg... Ooof. This one is a tough call. Luthor is always played as a highly intelligent, but still slightly physically dangerous individual. When you see Lex Luthor, you should think that this guy could not only know of a way to kill you, but have the will power to do so instantly. A wolf among men. Eisenberg just doesn't have that "look." He needs to have a presence of intimidation. All that patent Eisenberg passive-aggressiveness would wear the heroes down over time.
“Lex Luthor is often considered the most notorious of Superman’s rivals, his unsavory reputation preceding him since 1940. What’s great about Lex is that he exists beyond the confines of the stereotypical nefarious villain. He’s a complicated and sophisticated character whose intellect, wealth and prominence position him as one of the few mortals able to challenge the incredible might of Superman. Having Jesse in the role allows us to explore that interesting dynamic, and also take the character in some new and unexpected directions."It appears that he is going for a super nerd version, and I am kind of worried for this film. There's a piece of me that believes this movie will end up like Sucker Punch. Will Snyder make Luthor a man to rely on what he expects of others to do rather than his own intellectual superiority?
I suppose it's still a better choice than Michael Cera.
Granted, if he pulls this off it could be amazing. And after Now You See Me I actually do think he might be able to do this. We'll have to just wait and see. Perhaps he'll nail the xeno-hatred of an alien (from Krypton) destroying his beloved city.
EDIT: I thought about this a bit more and I really do think Eisenberg could do this well if he plays Lex as the super-rich, super-genius mastermind. No up and coming rich kid crap. Lex is someone that is capable of manipulating the entire population into thinking he's a hero, while secretly battling Superman. He is also someone that is able to go toe-to-toe with Batman (Bruce Wayne) in the business world. The easiest comparison would be an evil Tony Stark (Iron Man). He needs to exude unflinching confidence in his power as a tactician in both battle and business. And I think he can actually do it.
Source [ The Mary Sue ]