Much as I love the 1st Christopher Reeve movie, it's got its flaws. There's a lot of cheesy humor and it doesn't deliver on the kind of action climax that I'd like to see.
I'm not sure what you mean. With Superman, the kind of action that defines him is more about rescuing people and stopping disasters than fighting bad guys (since so few villains are a physical match for him), and S:TM has a lot of that kind of action in its climax, with runaway nukes and earthquakes and dams bursting and train tracks breaking and so forth.
Granted, though, the sequel's massive fight between Superman and Zod's trio was a very impressive achievement for its day, the first time that kind of big superpowered battle had been captured on the screen in live action.