I believe The Dark Knight Returns was one of the worst things to happen to Superman, & we are still (sadly) feeling its effects all these decades later.
The fact that the trailer for "Batman Beats Up Superman (Again): Dawn of Dark Justice" has Batffleck in the ridiculous armor & faceplate as he "squares off" against the "untrustworthy alien" is just one example. Batman, again encased in silly armor, disposing of the entire (Joker-envenomed & thus weakened) Justice League fairly recently in Batman's own book, is merely another example. You guys & gals are all sophisticated readers; I don't need to list off the totality of the dumbing down that Superman gets at the hands of the writers when batgod is around (not to mention the same treatment meted out to all the other powered heroes in the presence of Bruce Almighty) . It's practically proverbial at this point. Where do you think the inane phrase "Batman & His Bitches" w/regards to the Justice League comes from? It's b/c writers feel the need to power-down the rest of the Leaguers while simultaneously giving batgod yet another power-amp so he can try to keep up. It caters to batgod fanboys wet dreams...
And it all started w/TDKR.
Any possible subtle subtext about the political message was mostly drowned out by people who still say, to this day, that it was the book "where Batman beat Superman." That's all most people remember about it or know about it if they haven't read it. Even the quote from TDKR when DC announced the new movie was the "the one man who beat you" bs. A whole book of possible quotes to choose from (more, if you're not limiting yourself to TDKR) & that was the phrase they selected to inaugurate the movie to the world.
It all goes back to that aspect of TDKR.
The incredible thing to me is that the other half of the "dark 1-2 punch" in 1986 was Alan Moore, & his Watchmen made TDKR look absolutely idyllic by comparison. This makes him for the intents & purposes of this post the "king of the dark writers for the mainstream" back then...& this is THE SAME GUY who penned 2 of the most beloved & memorable...& frankly beautiful...Superman tales of all time. Of course I speak of "Superman: Whatever Happened to the Man of Tomorrow?" & "For The Man Who Has Everything." He was the writer DC chose to literally close the door on the Silver Age w/the former story. And he had enough sensitivity & breadth of understanding to craft both the dystopian Watchmen and handle Superman very well & respectfully.
Miller in TDKR? Not quite so much, as they say. Superman, in a lot of ways, is still reeling from his treatment in the pages of The Dark Knight Returns. Hasn't been good for Superman on balance.