While not to "replace" jesus, many of them draw on the "Jehovah/Jesus/man" story line.
Perfect example is Superman, where you have Jor-El, giving his only son to save the world. Especially when it was done for the 1978 movie.
They can be a great people, Kal-El, they wish to be. They only lack the light to show the way. For this reason above all, their capacity for good, I have sent them you... my only son.
AND you have that shot of Kal-el above the earth in a crucifix position in the recent movie.
AND, their name is "El" (house of El), a common prefix in many of personified names of God. (Shaddai, Elyon, etc)
from Superman returns
Lois:"The world doesn't need a savior. And neither do I." To which, Superman responds, "You wrote that the world doesn't need a savior. But everyday I hear people crying for one."
in the comic canon, Supes dies, and got back up. They even used the the iconography of "the tomb is empty!"
ya cant have Supes without Jesus.
and here's a bonus. Supes was made by Seigel and Shuster...... Jewish people.
And Jesus was born of.....Jewish people.....