My biggest issue with Eisenberg was his performance. He felt like a cartoon character. Like he was in a completely different film than everyone else.
...Lex needs to be grounded and real, with gravitas. Not quirky and crazy.
Certainly, Eisenberg’s Lex was weird, quirky and idiosyncratic. But I suspect that his weirdness, per se, wasn’t the main objection. After all, there are many genre supervillains who exhibit peculiar and eccentric behaviors and manners of speech. Rather, it’s a question of fidelity to the source material. And apart from Hackman’s campy, “cartoony” characterization, modern Lex is usually depicted as cool, suave — maybe even charming.
BvS, obviously, didn’t go this route.
The argument about being in a "different film” has, I think, some validity. Characterizations should be consistent with a movie’s tone. Thus (for example), DeVito’s Penguin was fine for
Batman Returns while Farrell’s Penguin was more appropriate for
The Batman. Ostensibly, they’re the same character; but they’re obviously
not interchangeable. So, by the same logic, Eisenberg’s Lex doesn’t fit into the dark, grounded sensibility of
BvS. Well… maybe. But, speaking for myself, I never found Eisenberg’s unconventional interpretation of Lex to be especially discordant with a serious, “real world” milieu. And, alas, this is a view that’s easier to defend nowadays. Consider the over-the-top bizarreness of Trump or Musk and you might convince yourself that those guys are in a “different movie.” Unfortunately not.
Steering back to
Legacy, I have no objection (at all) to a more traditional/conventional Lex Luthor. But I also expect one who’s a
serious antagonist — a bona fide threat to the world and to Superman. So just looking and acting the part (e.g., wearing expensive three-piece suits, speaking eloquently and NOT being quirky) is small consolation if Lex’s Master Plan is something akin to Hackman’s goofy real estate swindle.