Well, personally I would have him do a quick scan of the room with his X-ray vision, disarm the bomb and be like "do you guys trust me now?" and had him save the day. Cause you know...Superman. Thats what I mean about the sloppiness of the film makers, they can have him hear a gun cock to lois's head, but he doesnt suspect anything about a senate hearing? See, I didnt see all those emotions you said that he conveyed in that scene. The look on his face was like he spilled a jug of kool-aid on his carpet. Like "awww man". And why would he trust humanity? Does anyone trust humanity? If he learned anything from when he was a kid to an adult, and the 18 months between Zod and the events of BvS, is NOT to trust humanity. Thats the thing though, he isnt supposed to trust humanity, he is supposed to be their guiding light. Even Jor-el says something along those lines in MoS, is that he is the beacon of hope, and he stands resolute in his beliefs to do good. Fight the never ending battle...Not whine about how people dont stay good or whatever, I forgot what the line was. Like Dan said, he didnt embody the character of Superman. Seriously, Zach Snyder just doesnt get the character. Bryan Singer sort of did, but the story was lame (kid) and he put all the gay undertones on it because Singer is gay. Aside from a few comics, there hasnt been a good interpretation of Superman since the Donner movies.
He should definitely be less trusting considering how he's being put on trial for the actions of someone else and how MoS ended (trashing a UAV trying to spy on him). I think he's still just very naïve and that's always been the connection between him and Batman. Batman keeps him grounded with his cynicism and complete lack of trust with anyone. Superman believes that there's good in everyone until he has absolutely no choice but to believe otherwise.
I think he walks a fine line in any universe. If he guides humanity too much, he becomes a tyrant. Like in Justice League (S2EP11/12) A Better World. Superman became so hyper-vigilant that he practically paralyzed humanity, not allowing them go in any direction that was perceived as aggressive. If he doesn't guide them enough people ask "why weren't you there? Why didn't you save them?" He can do the heavy lifting by keeping the overall population of the planet from destroying themselves, but it's up to humanity to pick themselves up and realize the savagery of their actions and actually change.
The scene at the Senate hearing where he's standing in the flame, in my opinion, was that he was just hollowed out by the brutality of one person. When his existence is being questioned and people saying how he could wipe out everyone... yet regular people are so filled with hate, anger, greed, and jealousy that they commit the acts they're so afraid he will. I imagine his thoughts being something to the effect of "How do I save these people from themselves when they do things like this?"
I feel like Batman's part in this movie was a little harder to swallow. I get that the Affleck Batman is supposed to have lived through so much misery and pain in Gotham and that he's seeing the futility of his efforts and has become jaded. But it also felt like the subtle hints of what the Joker did aren't enough to give weight to his "If there's a 1% chance we need to kill Superman" point of view, only to be quickly swayed back on course when his mother's name is spoken.
I had 3 major issues with this movie and I think they're probably all a mix of Snyder and the studio.
(1) Lex - SO over the top and eccentric in most of his dialogue. I caught a few moments where he talked like a normal person and it was a relief and tolerable, but then he swings back into the contrived, forced over-acting (which is what I'm expecting from Joke in Suicide Squad as well). I thik if Eisenberg was more Zuckerberg and less Willy Wonka he'd have done fine.
(2) Doomsday - A CGI mess that barely resembled any previous version. I would [barely] even be willing to forgive the "origin" if it just didn't look so horrible.
(3) Snyder - He clearly has no understanding of the characters, no grasp of realistic dialogue, and no concept of good story telling. He's a kid given nuclear bomb to play with. No idea how to use it, what it is or how it works. So we end up with needless explosions and chaos.
While everything done is this movie seems to hinge on or be connected to a previous scene... those reasons, when broken down, make no sense.
Example: Asking senator Holly Hunter for an import license of the kryptonite. The whole Batmobile, chase, first BvS encounter hung on getting the kryptonite that was being brought in (as far as I can tell, illegally anyway). The whole "Grandmas mason jar of **** peach tea moment before the Senate blows up... also hung on the same scene. Yet, he has a team of mercenaries coming and going, killing, and stealing without any apparent issues. He puts a "silver bullet" label on the Kryptonite, asks for permission from a woman who is clearly on the fence about her position with Superman, to bring it into the country. Why say anything? Lex Luthor couldn't come up with a craft way to bring in a big green rock that was enough under the radar that Bruce Wayne wouldn't be able to track it? Sloppy writing for the sake of propping up other sloppily written scenes.
I'm relieved and excited Snyder won't be as hands on with Wonder Woman. I think that movie could still save this franchise.