That sounds bad and is likewise totally unfaithful to the story. Kraven’s obsession with Spider-Man is consistent to the core and theme of his character and it only works with Spider-Man and specifically a Spider-Man who is older and married. Kraven is a hunter who believes that by defeating an animal and wearing its skin he can become that animal. In KLH, Kraven fixates on Spider-Man’s totem at the expense of the person underneath. He doesn’t care who Spider-Man is beneath the mask. But it’s Peter’s humanity, his capacity to love, to retain that which elevates him above Kraven who has no family, friends and loved ones.
The last thing Superman needs in movies is more Lex Luthor. With the exception of Superman III with Richard Pryor every Superman movie has had either Zod or Luthor as an enemy. Dude is overexposed at the expense of actually interesting stuff in Superman’s corner.I could also see a "Luthor" film showing this ruthless ambitious genius work his way to the top of the heap - like "Goodfellas" meets Bill Gates, tell the tale in a way that actually mirrors what we all know about Superman/Clark's development and really set us up for how Superman's appearance impacted the world, totally F'ing up all his plans and his ego before they even met and why Lex would be so fixated on ruining Superman.
A Bizarro movie could work in the way the tales of Bizarroverse did in the Silver Age but the problem with Bizarro is that the comedy really works as a contrast to straight and narrow Superman and you need to establish that. It would have worked after the first two Reeve movies or even Superman Returns but not with Zack Snyder’s take still fresh as a bad taste.