Hahaha, if you hadn't posted here, I would have anyway.
Because I just had a thought...I haven't seen this anywhere on the CC yet, so correct me if I'm wrong, but...
The Fall of Guardia would have happened regardless of Lavos' defeat, ne? Lavos didn't directly influence Guardia or Porre, and some of the sidequests pertaining to them (the Sun Stone/Moon Stone thing) were optional.
Not only that, there's no one who's heard of Guardia in 2300 AD, no Guardia Dome...No Porre Dome either, but whatever, it might be too far forward in time for ANY previous country to exist.
Pretty sure Dalton getting sucked into a wormhole was going happen at some point anyway, either at his defeat, OR (in a non-time-travel scenario) at the same time as the Gurus and Janus.
But seeing as Guardia would have fallen at that time anyway, a story could presumably be written as if Crono and Marle had never met, time-traveled, and saved the world. Crono would take his sword skills to the Guardia military, Nadia would continue to be the trapped princess (who had somehow gained some freedom at the fair before being brought back to the castle), and they could conceivably meet for the first time the night of the invasion, Porrean troops closing in, Crono helping to defend the castle, Marle picking off soldiers with her crossbow...
A Future Refused to Change Story that has nothing to do with Time Travel...
Just an idea.