One of Luthor's more interesting scenes was when he was giving the speech.
It was straight word salad, him trying to connect knowledge, power, greek figures into a disjointed and bizarre thank you speech to the donors present and being clearly unsuccessful at it. It was a small scene, but it was oddly fascinating to see him caught so off guard by something as mundane as having to talk to a large crowd. Which is why I believe his manic mannerisms aren't an act. I mean, otherwise, he just kind of embarassed himself publicly for no reason that I can see.
I'm not sure what the purpose of that scene was, other than to get the crowds attention away from Bruce so he can do his spy thing, but I find little, fundamentally meaningless scenes like that often add a bit of personality to characters. It shows there's more to them than the existing plot. I don't like this Lex Luthor, and I wish we had gotten one that was more normal, but I would still say that he's one of the lesser evils this movie commits. The worst thing you can say about him is that his motivation to hate superman isn't really coherent, but he's hardly the only one in that catergory.
