It doesn't have to be a Reeves homage but he could inject some Silver Age fun into the 90s-style action. Classic hero archetype action with modern angst sort of.
You aren't going to get the most out of Bizarro, Mxyzptlk, or even more serious villains like Brainiac if you don't have a little self-awareness. Even Clark's relationship with Lois can use some flavor. This Superman can be as serious as the director/execs want but the source material can put him in all sorts of situations that flip his/the audience's perspective. Like if he found Supergirl or Kandor. Or Krypto?
I think sticking to the epic/mythical/serious take on its characters would help differentiate DC from Marvel. I'm all for that. But we can have fun without distracting from the story like the competition does sometimes.