when Superman goes back in time, he removes himself from the equation--he's not on the planet moving backwards, reversing all his actions. He's up in space. He's not down there. Lois died because he WASN'T there, so he reversed time to when he could be. But the pregnancy is different because he WAS there. So you can't take back the sex, because he's not on the planet humping backwards in reverse. There's nowhere for the sperm to go back into. She's still pregnant by the end of Superman II, which is essentially the end of Superman I.
Dude, haven't you ever seen a time travel movie? When time is reversed, EVERYTHING is reversed. It doesn't matter where anyone physically is at the time of the reversal-- that's just goofy. Time doesn't know where you are when it's being rewound. And if you use Back to the Future's time travel "rules" as a guide, as soon as you create another timeline via time travel, a second time traveller is also created, hence Marty seeing himself at the end of BTTF I. He went back in time and came back, creating another, alternate timeline, and another Marty. While the time-reversing Superman is spinning the earth around, the Superman that was in the first, Lois-dies/Lois sex timeline is also being reversed. After time is rewound, Lois is alive, and Superman did not bang Lois-- that's the result of reversing time, chief. Plus, Lois is not pregnant by the end of Superman II, is she? (no one knows if Clark brought his Trojans or what)-- the pregancy was a sloppy Singer device/assumption that just because they had sex, Lois is automatically pregnant so the kid character could be added. HOWEVER, all of this is meaningless when considering that fact that if you reversed the rotation of the earth, time would NOT rewind, but continue forward, with the earth just spinning in the opposite direction. Sort of how in Ferris Bueller's Day Off, the miles on the car continued to go up, even though the car was in reverse. And if the earth's rotation was suddenly changed, everything on earth would shift and fly around. But the effect looks really cool in the movie, and it's a movie, and it's Superman, so whatever. And for the record, I thought SR would've been a more interesting movie if the kid turned out to NOT be Supes'. Superman just doesn't go around having kids, even with Lois Lane. [And why the fuck is Superman's child asthmatic?]
The kiss has been there for YEARS now, one fourth of a century
That is the lamest argument I've ever heard. Superman II itself has been there for 25 years, too, but that didn't stop the Donner cut from being released, or any of the countless alternate cuts of movies from all eras for that matter. The kiss will remain in Richard Lester's Superman II for all eternity. We're talking about a NEW edit here.
The bottom line is, Superman Returns is IRRELEVANT to making a new, ideal Superman II. Bending over backwards to link them (when Singer's links are more homage/rehash than continuation) is akin to Lucas altering the OT to fit the PT. It's all about making the best Superman II story. A bigger question is: should Superman II.0 be assembled with regard to making the best sequel to Superman: The Movie, or just the best version of Supes II? What everyone is forgetting is that Superman Returns is ALREADY connected enough to the pre-existing I and II, so again, for the purposes of making a better Superman II, it can be left alone on its own merits (or lack thereof).