I doubt it. Franky clearly observes that Luffy is stronger than him.
After being useless against Lucci, and see Luffy hit him. he says, use that punch or move or whatever he says to beat Lucci. he doesn't say, if i was full of cola, i'd mop the floor w/ him.
anyways, i love franky's character, he's totally awesome, but i don't want him to join either. i'd prefer that he be the one to provide the SH their new ship, and that be it for him. but, the way the evidence is stacking right now, it looks like Franky will be the new member. no one else fits the part at present, unless Oda pulls some new/old side character out of the woodwork and claim them to be this awesome shipwright. As much as i'm against it, i can't see anyone beside Franky being the new shipwright. Paulie is probably still a possibility, but he has been cast aside w/ the side character roll.
with Vivi, i was so hoping she wouldn't join the crew, though the invite was nice, i'm glad she stayed in her kingdom. and then when robin joined, as luffy said, she wasn't that bad to start with, so it was understandable. the difference i think now w/ franky is that though he started out as the bad guy, he has pretty much won over everyone as robin had won over luffy. anyways, i'm just rambling right now b/c i want to go home and i have an hour left at work
i'm still crossing my fingers for something different, but it's looking alot like Franky will be the new strawhat until the new SH/shipwright is officially revealed :)