The only reason I'm somewhat relieved they are most likely keeping it as Clark (even if racebent) is that if they did a Calvin Ellis or Val-Zod movie and it was a hit, I don't for a moment trust WB to not retire Clark from films indefinitely and just focus on making movies with the others. It would be the last "**** you" to Superman. It wouldn't at all be the fault of the other characters, but I wouldn't remotely put it past this studio to find a way to make money off the name and symbol but abandon the actual main character to make life easier for themselves.
Under ideal circumstances where we had a shared film DCU (or just a Superman universe) that wasn't a mess? We'd get a Superman's own films and spin offs across his franchise and multiverse: Supergirl, Legion, Steel and Calvin Ellis. It'd be neat to see Calvin and Clark team up, Calvin getting his own movie and/or leading an ensemble cast in a Multiversity movie.