tbh i don't believe fontaine was rewritten, simply that they purposefully wrote the most self-contained story they could to mimic an opera. chapter 1 is "prelude of blancheur and noircheur" with the climax of chapter 5 happening in "the opera of noircheur and blancheur", and the first quest where we meet furina is "soloist's prologue" and the final quest of the series is "finale". the issue is less that the story was changed and is bad now and more that to begin with, it only ever focused on one point of fontaine's history and was hyperfocused on dealing with that. even most of the world quests have to do with solely the prophecy, or completely ignore it in favor of modern issues (which...honestly it kind of ties nicely into focalors' "continuation of that existence" when i think about lanoir, morticia/the gang, etc.). fontaine has a lot of unexplored history, partly due to being sunken, and also because most npcs don't give a shit unless to write folk legends about it. but it's still disappointing as a player because we had all these questions and interests that didnt get answered or acknowledged.

that thing about "sq2 being delayed due to sigewinne" thing tho, there were 2 things from sigewinne's SQ that i can understand needing to be tackled before the archon's sq2. the first is the end to the vacher/sinthe saga, and the second is the reveal that dissolved fontainian juice still retains special properties. and personally but i feel like aremori castle and "pools of pure water" the lochknights guarded could be coming up simply because...well we already have the north of fontaine but i dont see castle ruins or any oceanid birthing pools. and after 4.6 and 4.7 where they minimally mentioned the lochknights while focusing on the marechausse hunters...feels kinda suspicious but thats just me.