Cheb wrote:In this particular case, not intervining Ranma's world line tightly with the straw hats' world line is a *bad* thing.
If he's not with them, he's somewhere else. And you have to build/detalize the OP world around him. All by yourself. That's a lot of work, a mighty challenge, and people could doubtful if you can pull it off.
What's worse, OP is far from finished, OP has a very interconnected universe vital parts of which weren't uncovered yet, and in going away from the Straw hats' worldline you have a very real risc to running head first into contradicting canon as something important is revealed a the nearest future. Cue all the alternate theories about the nature of Kyuubi written before Juubi and Rikudo Sennin were revealed. Granted, some of these are really good fics - but would you take responsibility for your fic *suddenly* turning to be an AU?
Running the character crossing over off the tracks is an arduous task. It often requires to have as much skill for expanding the universe details as the original author does have.
That is actually an irrelevant question. If you have an idea for a story, why should you change that idea in the middle just because something that came out later contradicted something in your idea?
It just isn´t realistic to try and write like that. And i´ve seen far too many excellent fics turn really bad because a writer tried to change the story to adhere "better" to canon.