I tend to agree that Superman was no different than any other hero in that respect (friendly with authority figures, etc.) in the '50s and '60s. I've never read that story of Miller's (just not my genre), though I don't like the sound of it. Do hate what happened to Batman which Miller certainly set in motion, but can't deny the commercial success.
Superman has gone through lots of changes. I don't like the deathbed instruction, and do think it screams CCA (and is rather clunky and poorly executed). There was tons of upping (really flat-out creating) Superman's connection to his Kryptonian heritage in the era and distancing him from regarding himself as human. I'm not fond of it at all, but don't think it was done to "fix" anything, but rather just normal character changes and taking advantage of sci-fi being popular in the 50s and going a route that would sell well. Don't care for the rewritten origin making Krypton a depressing place.
I actually find the movie responsible for a lot of issues, which may be strange to some, considering how beloved it is. I hate the "Jesus Superman" motif, which has at least been prominent in movies (haven't noticed very much in comics, but certainly haven't read entire library). For me, Kal-El was sent away to save his life, nothing to do with being intended to guide or lead or save humanity. If the planet hadn't been about to blow up, they have kept him there and raised him. Also for the "naive farmboy" or "salt of the earth" or whatnot, ascribing wholesomeness and honesty to small towns and Clark's cover persona or Superman's values. Yes, he originally grew up on farm. Because farming was a very common occupation in the 1910-1920s. It wasn't some fundamental important part of him that he must be rural or that his values could only be obtained in such a place. And he wasn't treated like some sort of bumpkin compared to everyone else, nor did his values seem to differ from those of the city-folk around him.