Makes you wonder what Donner's plan for Lois' death originally was. Maybe she wasn't going to die in either film originally and they threw in her death when they moved the time-travel to the climax of the first film.
I think Clark beating up the trucker works if you show that scene
before he turns back time. In fact, that would probably be the
best version of the scene...Superman isn't worried about injuring the guy too much because he knows he's gonna wipe the timeline anyway so might as well take the chance to indulge in some petty vengeance
But yeah, Superman's time-travel/reversal is pretty much a story-breaking power in these movies. The way it was shown in the first film, it works on an emotional level at least - Lois' death making Superman grief-stricken enough to defy his father's warnings and turn back time. Though it does raise the question of why he doesn't do it
everytime someone dies...
In the Donner Cut of the second film though, its even worse. He basically reverses time just to wipe Lois' memories of his identity! At that point, there's
absolutely no reason why Superman shouldn't just reverse time to wipe out
anything that is mildly inconvenient to him, let alone a serious threat!
I've never been a fan of Superman being able to freely time-travel for this reason...at least in the Silver Age comics they were careful to come up with explanations (however weird) of why he couldn't change anything...