Superman is more than a comic book character, a movie character. Superman long ago entered the national soul, and has become a symbol of the best this nation has to offer... in action and in heart.
Part and parcel of this is his costume. While this design has been altered and tweaked over the decades of his reign as iconic comic character and pop culture phenomenon, most of these changes have been minor- and relatively short lasting.
Because the classic design is the one that comes to mind whenever the character is thought of or evoked.
But they keep trying. Recently removing the red modesty briefs, or trunks from the costume. To us, this looks odd, singularly immodest for a good Kansas boy, and awkward. Please- as a fan, Mr. President- urge DC to BRING BACK THE TRUNKS!