Lois Lane.
Hoo boy.
Let me get this out of the way and say that I like Lois. I am a fan of Lois Lane. She's pretty cool. But more than that, she's interesting.
Lois is that rare breed of character who's really well rounded, has a solid, believable and really emotionally resonant backstory, has a lot of layers to her, and pretty much has a supporting cast of her own with her dad, her sister, her sister's husband, and Perry who she has more of a relationship with than Clark does, but despite all of that, at her core, she's still largely defined by her relationship with another character.
That character being Superman.
Duh.
She's Superman's girlfriend. Or wife. Or girlfriend then wife then girlfriend again because Grant Morrison is a butthead sometimes and did you know that the entire reboot was just one giant dumbass excuse to break up their marriage and recreate that stupid ****ing love triangle and okay I'll stop but we WILL be talking about this later!
Anyway. Point.
She's Superman's girlfriend. That's the label that she's carried with her for pretty much ever. It's the role she always fills. She's the archtypical superhero girlfriend. She's the reason every super hero movie has a shoehorned in love interest who doesn't add anything to the plot and isn't particularly interesting. They're all derivative of her.
Because she's more or less defined by that role, her characterization and general role in the stories is much more effected by the times and by the writter than Superman himself, because she's pretty much a slave to whatever the current author's view on love is. I think the best example of this is contrasting her protrayal in the very early days of the Original Seigel Shuster run with her portrayal in the Silver Age. In the first ever Superman story, Lois was pretty much the main character. We found out about Superman through mostly her point of view, and she initiated the plot with her gung ho journalism, Superman's role in the story was pretty much "Oh, I've got to save my mean yet oddly hot coworker. Again. ****." Well, that and being a weird alien guy in a blue costume.
Then look at her in the 60s. She's shrill, boy crazy, petty, kind of a sociopath, kind of insane, etc. While in the 30s Lois was based on the then not quite contemporary but still within recent memory Nellie Bly and served as our introduction to Superman and his two fisted pulpy adventures, in the 60s with all of their weird sci-fi regurgetated nonsense she's pretty much devolved into every horrible female stereotype that was popular at the time.
And that's the problem Lois has almost always faced as a character. Since her primary role is "love interest," she changed depending on whatever the current writer thinks about love.
The biggest thing about this is how it ties into the whole "Is he really Clark or is he really Superman" debate. I know that might seem like a tangent but I really don't think you can bring up Lois and not bring this up to. Whatever approach you take to Superman, it has a huge impact on the character of Lois Lane. Which side of his personality is the "real" him says a lot about her falling in love with him and the nature of her feelings for him and wether or not she's shallow or callous or confused or whatever.
If you go with the idea that Clark is who he really is, then what you're basically saying is that what Lois Lane inititially falls in love with is the idea of Superman, the symbol he represents, and it isn't until she and Clark grow closer and he reveals his identity to her that she falls in love with the man.
If you go with the other way around, what you're saying is that she falls in love with the man he really is deep down inside that he wishes he could share with her but can't because circumstances won't allow it.
Both of those are interesting. Both of those are, in my opinion, pretty cool. But they're both pretty different.
For my money, I'm actually not a huge fan of either, just like I think the Clark/Superman split is a false dichotomy.
The way I prefer Superman, and the way in which I think he has the most nuanced and interesting character, is the idea that both sides are the real him. When he's Superman he's being himself in a way he can't as Clark, and when he's Clark he's being himself in a way that he can't as Superman, and he can't be completely himself at all times because circumstances won't allow it. I like that idea because it seems more real, it creates a lot of conflicting needs and desires, it's a much more complex and psychologival take on the character, and I think it just makes more logical sense.
In the same way I think I prefer the love story angle that one would extrapolate from that. Lois does fall in love with the inner coolness and strength that shines as Superman but is hidden in Clark. But at the same time, Superman is kind of whitewashed. He's processed for mass consumption. Clark has to make himself appear to be perfect as Superman for the sake of the symbol that Superman is. As Clark, he's allowed to be in foul moods and have a kind of messy apartment and me snarky and act goofy and say dumb things and like dorky ****. As they grow closer she has to deal with the fact that he's a person, not just a concept of a person, and I think that's much more real and much more interesting.
Either way, that's what makes Lois fascinating from a narrative standpoint. She has this really well defined personality, but at the same time it fluctates wildly based on the writer's style and approach because she's still stuck in the role of the love interest, and every writer handles the love interest differently. Silver age Lois, Golden age Lois, John Byrne's Lois, Movie Lois, they're all reconizably the same character, but with how wildly different they are you'd think they shouldn't be.