I think Cavill is back for more than just cameos, and we’re going to get confirmation after BA opens, i.e., solo Superman films and Superman in JL films. David Zaslav said this is what he wanted right out of the gate, it was in the first trade article after the merger completed.
Similar to what I suspect was a publicity stunt of inserting Josstice League footage into the Black Adam trailer, so that the Rock would tweet “corrected” after they changed it to ZSJL, my guess is that the Williams score is also being used as a publicity stunt to “show” that the fans are being listened to, heard, and respected.
If fans speak out against the Williams’ theme being used—or rather simply express that they want the Zimmer score—I am sure WBD will change it to Zimmer’s.
Jay Oliva (Snyder’s storyboard artist) has said that early in development of MoS Zack inquired about using the William’s theme, and it wasn’t available for whatever reason. But this is what Zack Snyder actually had to say about it:
It’s crystal clear that Snyder never intended to use the Williams theme. He’s saying that whereas William’s theme expresses the “glory” of Superman having godlike superpowers, Zimmer’s more tender mood captures Superman’s humility. Like once he realizes he has this power what is he going to do with it? And he’s incredibly humble about it.
Henry Cavill’s Superman is a more thoughtful approach that reflects our real world much more closely than the classical Donner/Reeves version based on the Golden and Silver Age comics, and the 1950s TV show. This theme should be maintained also to honor the arc that the character is on and will continue to be on as he evolves.
If you‘re on Twitter get on there and express yourself if you want for the Zimmer theme to be used instead of William’s.
As for the suit, personally I’m fine with blue/red/yellow in brighter tones. If/when Snyder ever returns to make JL 2 and 3 he can always put Superman in the black suit again to maintain consistency with what’s shown in in ZSJL. That’s not a big deal. Snyder explained that he put him in the black suit to for Superman try to get in touch with his Kryptonian heritage and relationship with his family. Presumably he bonded with Jor El’s AI and learned much about his ancestry and Kryptonian history on the scout ship. Snyder typically wants us to us connect those kind of dots.