But Franky has a major dependancy (the FF), while Paulie has none (the Galley-La doesn't need him).
Errr… so Iceberg and his life-work is in a crisis and you think Pauly will just leave his idol into the mess and won't help him to rebuild Galley-la (and the city, as Aqua Laguna wasn't just a bunny wave). I still don't get how Franky is dependant to Family, or even opposite, please explain. Quoting his own words his free as a bird.
Edit: Irre put it together way better.
Edit #2 @GunMetal
Could be but I doubt it. It would be way too irresponsible and he had over two year of time to design the shipwright, he wouldn't change his mind after that. The way I've seen it is that Oda just used the Galley-la (especially Pauly) for distracting readers from the real candidate. While readers were debating whom of the Galley-las it would be, Oda surprises us with an outsides - with a character we didn't even knew actually having a chance. Much like with Chopper, Franky was just a silly background character nobody really noticed until he was actually given attention. It's often used trick of writers.