Yes I like a clone story when it turns into a tragic Flowers for Algernon thing. The Superboy TV show basically did that with Bizarro and despite his horrible look in that show, I thought they did a pretty solid job with it.
Exactly!
@dhandler01 since you said you have a hard time seeing the whole picture, this is my rough guess at a potential way the film could play out.
This is a world of heroes. Most like Terrific, Hawkgirl, and Guy are part of officially sanctioned/corporate sponsored teams. Along comes Superman who goes about things his own way and according to his own moral code. He can do that because he is more powerful than anyone else.
There is some sort of international crisis, Supes intervenes in an independent way taking no sides. The US government doesn't like that because he makes them look bad for picking a side. He starts to inspire the other heroes to act independently. The gov decides he is a threat. They commission Luthor to make them their own Superman they can control.
Luthor makes a clone, Ultraman. Clark gets really mad when the doppelganger does something horrible. Confronts Luthor, gets arrested by Ultraman. Ultraman starts to want to be Superman. Takes the suit. Tries to be Superman but starts degrading and people are scared of him.
Ultraman/Bizarro lashes out by getting something from Luthor's labs or the Fortress or something to remake the world in his distorted image. Luthor has lost control. Superman needs to be freed to face this threat. Big third act doomsday sequence that requires Supes to work along side a newly independent JLI. During the process, Supes convinces Bizarro to change his mind by being compassionate to him (not reacting in horror). The threat basically needs a Kryptonian to sacrifice themself to save the world. Supes is going to do it, but Bizarro having been inspired does it himself.
Superman ushers in a new period of independent heroes who just do what is right and not others' bidding.
There is a bunch of missing elements, but that is conceivably how I could see a big chunk of the film going.