I don't agree that recycling the John Williams score would've been "right." People keep forgetting that Williams's theme was itself a pastiche of the two seminal Superman marches, Sammy Timberg's from the Fleischer cartoons and Leon Klatzkin's from the Reeves TV series. Williams is just one of many composers who've created new Superman fanfares and marches that followed the stylistic lead of those two, and some of them have done lovely work. Personally I'm quite fond of Ron Jones's theme from the 1988 animated series and Jay Gruska's from Lois and Clark
. Shirley Walker's S:TAS theme is pretty good too, and Louis Febre gave Clark a pretty good heroic motif in later seasons of Smallville
. Hans Zimmer came up with a good Superman theme at the beginning of the end title music of MOS, but he barely used it.
I suppose the reuse of the Williams theme in SR could be justified because it was theoretically a continuation of the same version of Superman, but I didn't care for the way it was used. John Ottman didn't do any fresh adaptation or variations on it, didn't arrange it to fit the sequences it accompanied; he just slavishly replayed the theme music note-for-note every time Superman did something, and it felt lazy, repetitive, and heavy-handed.