The problem I see is that Superman was never meant to be realistic. He's an ideal, the embodiment of being a hero.
But, if I wanted realism, I wouldn't deal with superheroes. Even shows like Arrow are, in the end, fairly unrealistic, and thats fine. Superheroes are supposed to have an element of fantasy and fun to them. Its ok to be dark or realistic at times, but trying to do that the majority of the time just misses the point. The Marvel movies get the combination just right. They have serious moments and threats, but the heroes aren't just going off and snapping necks or brooding, even when things get really tough. Its a fine line to walk, because most of the time you don't want to go too silly, either (although there is a place for that with certain characters).
I hear you man. Not disagreeing with you at all. I've been following Supeman since the 90's and have read back to the 50's. I love the character, however I do think there are allowances that need to be made. A villain can't be a villain if he's only playing footsy with the protagonist. It would be dishonest story telling to show Zod is willing to go as far a total genocide against a planet's species (Loki tried the same thing against the Jotenheim and even committed patricide) but Superman is unwilling to kill Zod to prevent more death and destruction? With no tactical advantage over such an adversary, what should Superman do to defend himself and the people of Earth? It very well could've been Supes in that headlock, and Zod wouldn't have hesitated to kill him.
Rewatching the scene it's apparent that Zod wanted to die. All he had to do to escape was fly up. Instead he forces Superman to end his life, despite Superman's pleas that he stop. [yt]http://www.youtube.com/watch?v=CyPGlMXUwVg[/yt]
As for having more reason to kill, Batman shot Darkseid to stop him from keeping all of Earth (and eventually all of the universe) as his slaves with the anti life equation. Those stakes are a bit bigger than Superman killing Zod because he didn't want to move his head. Even if Zod had won in MoS, the effects would still have had less consequences for the universe than an anti-life equation equipped Darkseid, so I think Batman in Final Crisis was a bit more justified in what he did than MoS Superman.
I haven't read Final Crisis in years so I don't remember all the details. I remember Superman and Darkseid having a conversation after Batman "died". Which was followed by the Flashes leading Darkseid's own omega effect into him. Also Supeman creating the Miracle Machine to rid the universe of Darkseid forever. I need to read it again.
Zod in the comics had Pre-Crisis strength. Which displayed by Pre-Crisis Superboy and Superman allowed him to travel through time uninhibited, move planets out of their orbits, never needing to eat, sleep or breath (could be used for deep space travel) and have no quantifiable limit to their kryptonian abilities. Ever heard of Superboy-Prime? That's the kind of threat Zod, Quex-Ul and Zaora presented when they threated Byrne-era Supeman that they would come to his universe and kill more people. With the rules of Kryptonite being what they are. Outside of magic and red sun radiation, those 3 would have have terrorized Byrne-era Superman's universe if they escaped the pocket universe.
Superman is held to a different standard, that's just the way it works. While almost every superhero tries not to kill, its different when Superman kills someone. He's supposed to be the ideal superhero, the one people judge themselves against. Its fine for him to be a person, with flaws like the rest of us, but he's still supposed to be different.
Superman's oath to not kill is not supposed to hold up to real world situations, at least not as something that he never breaks. Just like how real people can't fly or dress up like a bat or get power rings. Trying to make heroes super "realistic", dark and brooding was root of the problems with all of the DC live action movies since Batman begins, but MoS definately used the worst superhero to try to make "realistic". He's superman, if you can't take him having a bit of fantasy, and hope, well then you probably shouldn't be telling a story with him.
The issue here is that Superman has to have credible threats, and villains to combat. As powerful as he is, Superman cannot have weak villains with weak motives. Remember his comics have to sell. So the writers and editors at DC take a lot of creative liberty with the character.
You look at villains like
Brainiac
Metallo
Luthor
Parasite
Zod
Doomsday
Darkseid
Mongul
Cyborg Superman
You think they're going to treat Superman with kid gloves? They are all very dangerous and are capable of killing Superman. When writing stories you want to be faithful to the character's abilities. It would be disingenuous to nerf these character's abilities and their potential to be great antagonists by not handling them as the threat they truly are to Superman and society.
Let's be clear, besides Doomsday and Pre-Crisis Zod with 2 accomplicies (who fought a weaker Post-Crisis Superman who had no knowledge of how to make a phantom zone projector), Superman has refrained from killing any of them. His biggest threats he always finds away to avoid killing them. Look at JLA Earth 2 by Grant Morrison for example. In it Brainiac had a mad plan to merge the anitmatter universe with a positive matter universe. The merging would cause a cascade of energy which Brainiac would use to become and Nth level intelligence. This of course would kill everything in both universes except Brainiac. Superman was ready to destroy Brainiac as he has no qualms about destroying a machine. It's not until he sees Brainiac of the antimatter universe that he recoils and becomes unable to act. Brainiac is an organic head in a tube in the antimatter universe. Superman could not bring himself to harm him, despite the clock ticking down and a decision needed to be made in order to stop Brainiac.
Villains like
Bizarro
Mxyzsptlk
Titanno
Livewire
Prankster
Toyman
Bloodsport
Silver Banshee
Kryptonite Man
Intergang
These are all less of a threat, but Superman always finds ways to handle them despite the degree of personal danger to himself. Bizarro being a clone of Superman, Silver Banshee with her killing scream, Titanno and Kryptonite Man who radiate kryptonite, Mxyzspltk with his magic and reality altering powers, and Livewire with her electric powers. Superman has not used lethal force against any of them. Not even Toyman who is a child murderer and a pedophile.
I think Superman is a great role model and an ideal. The world is tough out there, in fiction and IRL. Superman gives 110% in every adventure he has. What makes Superman compelling is he has these stories and villains to challenge him. The Zod's, Brainiac's and Darkseid's will always be the most evil and commit the greatest crimes against civilians. How Superman conducts himself against his strongest opposition, is what I think defines him to the audience he is presented to.
It was the honorable thing because it was established in the Superman canon of the time that if he ever broke his oath, he'd renounce his powers. He did exactly that. One can debate whether it would have been better for the world to keep a Superman who happened to have a body count of one, but the man kept his word.
Important words bolded by me. Times change and no one is advocating Superman become the Punisher or kill with regularity.
As for the end of "Whatever Happened To The Man Of Tomorrow", even as a teen I thought the ending ridiculous because there might come a time when the power of Superman is needed again to stop a threat only he could stop. He should've realized that and also realized that if you're in the business of entering into conflict with people who want to kill others, take over the world, destroy the world or the universe or something like that, then you're going to have to face the possibility of taking a life at some point. If you don't like that, then you're probably in the wrong line of work.
In "What Ever Happend to the Man of Tomorrow", I seem to recall Lois telling the reporter at the beginning that all of Superman's other enemies were already dead. Mxyzsptlk brought the remaining ones together against Superman as a way to kill and torture him.
I'm not sure anyone remembers the duel between the two Supermen from Infinite Crisis back in 2005-2006. Where the modern age Superman fights the Golden Age Superman. The dialogue they exchange puts our debate of changing times in to perspective sort of.