Agreed. I would say '"All men are equal" in legal and moral terms' though. 
Well, for example The Sword in the Stone can certainly be interpreted that way. On the other hand, you could also claim that the story is about Arthur needing to face his responsibilities as the Once and Future King. Lets face it, feudalism and absolute monarchy sucks from a modern POV. But that was what they had back in the day. Who knows what people of tomorrow will think of representative democracy, the market economy, socialism or the current de facto mixed economy? Whoever claimed that history "ended" in 1990 was incredibly foolish.
Mark Twain (The Prince and the Pauper) - and later Robert A Heinlein (Double Star) - made interesting twists on the theme.
This depends on what version(s) of the characters you mean. Only the Silver Age version of the Mort Weisinger era was truly god-like and invincible (except for the Achilles he-, I mean kryptonite of various colours). I disagree in general about Superman being boring.
Also, there is a lesson to be taught: With great power comes great responsibility. (Yes, I took it from Spider-Man, but it's still relevant.) There is a Superman story (which I haven't yet read so please excuse me for paraphrasing from second hand sources) in which Superman got elected for US President. (I guess an amendment made it possible for naturalized citizens to hold the office.) And he did not abuse his powers, or became a dictator. And when he had made his two full terms, he stood down. He simply was a honest and effective statesman.
Agreed. (But did he become Batman - mostly - because he wanted justice or because he -mostly - wanted vengeance? Either way he does help people, but still.)
