I think the problem with Superman is that for some writers he’s difficult to get right. He has so many powers, even invulnerability and his only weakness in terms of his powers are a variety of coloured rocks and the odd villian who can match him for strength or are near invulnerable. It can either be that they make him too perfect (as in the Gary Stu, perhaps even preaching why he is right) or if they don’t like him, can turn him into well… something that is hard to like at all and kind of a jerk.
In the end Superman is generally considered to be the idealised version of an American. And this changes as America’s overall view on this changes. However whose to say this idealised vision can’t have flaws? And after all, everyone has a different view as to what perfection is, to the level it could be said that it doesn’t exist.
What is justice and fair to Superman could be too strict or too lax to completely different people, depending on who you ask in hypothetical X situation, and if he existed in real life you just know there would be people in the media giving him grief too. Superman is also seen as the one the media in the DC universe looks to most of all. The #1 hero, and probably the first hero they’d think of not counting whatever resident hero is there (Batman for Gotham etc.). This can produce a unique kind of pressure even most heroes wouldn’t get. He MUST be perfect. He MUST be good and pure. And he has to hold back or else he’d probably break someone’s neck with his little finger. And other heroes look up to him too.
But perfection does not exist and he can’t really give it.
And for just a general character some virtues or talents can be also a failing or even a weakness. For instance the concept of lying:
If someone is GOOD at it, they can perhaps get out of certain situations and be important sometimes in even saving a life, but upon having this talent found out this makes it difficult for him/her to be trusted by perhaps even allies and loved ones. Plus of course there are ethical questions involved. Sometimes a white lie or a big one is needed, but you’ve got to know where to stop, and it’s possible for trust in general to be shattered. Those who are bad liars and/or engage in full frontal honesty? While they are more trustworthy perhaps well, as stated, there could be a life or death situation where you HAVE to lie. Or at least bend the truth. The refusal to do this or inability to do so can result in bad things. Even result in someone losing their life.
Basically Superman is in general a good person, and writing should reflect that. That he tries his best to make that good and ethical choice. But there are some things his powers can’t fix. He can’t bring people back to the dead, sometimes there’s a time limit on making the ‘right’ decision even super speed can’t help with, and even in some ways he’s a danger (like one of those pretty rocks making him go insane or simply an enemy engaging in mind control). However without this even in the end an interesting thing in throwing a wrench into the works is making it HARD to identify what is right or wrong and to throw the guy into morally ambiguous situations where there are perhaps good arguments or understandable consequences to the road he takes. Life isn’t a simple choice of good or evil for the most part. The hardest part in the batlle of ‘good and evil’ if we’re to use those terms at all can be identifying which is which! And many decisions can be a constant weighing of the two and the long-term and short-term impacts.
Also Superman can’t see into the future, so some impacts might not even be considered until they happen.
It brings questions like whether he should just kill Lex Luthor- because the guy is constantly getting away with it, and it’s something he did in an AU in JLU too. With consequences. Resulting in all of the JLU going too far and becoming the Justice Lords. Also in genearl killing villians asks questions like: where does it stop, when do they know when to stop? And who watches the watchmen? As it were.
In the end the JLU Superman still had the desire to do good as well as his own personal feelings. He wasn’t made of stone and he could be gotten to if not physically, emotionally. Batman mentioning how he’d been humiliated for instance and turned loose on people clouded his judgement in certain matters. He also could let his own paranoia rule him when it came to Luthor (which was paranoia that was pretty understandable and even true to an extent). He can snap and get angry, and even good people can especially when scared of what could happen. Superman is more emotional and open than Batman. This makes him more approachable for some. He therefore wouldn’t get upset if he didn’t care, but getting upset can also lead to the wrong decision. And JLU built up him cracking over a good long time with Luthor and Cadmus, it didn’t feel like it came out of the left field like how sometimes people try to with suddenly!jerk!preachy!Superman, trying to take him down a peg. And people were genuinely scared of him and the rest of JLU making for some great antagonists, especially in the case of my favourite DC antagonist of all time Amanda Waller and certain other Cadmus characters. She was understandable as well as utterly awesome without superpowers.
It’s understandable in JLU for Superman to be angry and upset and paranoid considering what he faces just as it is for Amanda Waller to join Cadmus and be willing to deal with Luthor in order to able to watch the Justice League, knowing what she knows and seeing what she’s seen.
Just make Superman a regular person with many powers trying to do the right thing with the stress of being ‘perfect’ and sometimes having to make morally complicated decisions and they’re probably onto a winner like with JLU Superman. Make things go wrong, make it turn out he made the wrong decision sometimes. Make him angry and pranoid about what might go wrong because he cares about doing the right thing, but make that anger also at times be a weakness.
JLU is definitely my favourite incarnation of him and I’ve yet to find one as good and relateable in all honesty.