Franky just doesnt fit into the crew in my opinion. He is too wierd. Not that that is a bad thing, but he isnt the type of person to join. His connections to water 7 and the franky's is too strong for him to leave. Plus he is…just too wierd! I mean come on! speedos? Who wants to see that every chapter?...besides all the people who want franky to join...regardless, i feel he is too random and sparatic and destructive...one might argue that luffy is too, but he is the captain. We already have comic relief in the form of Ussop/luffy combo. We dont need another freaken weirdo. Plus, I dont even think he is that strong. I think that individually luffy, soro, and sanji could beat him if they needed to. Plus, can you really see luffy and his crew cruising along the grand line in a freaken battleship? I cant. They belong in an good old wooden ship. Not a weapon of mass destruction.
Pauly, on the other hand, fits perfectly. He is in debt, constantly in trouble, but never acts as eccentric as our pal franky. As mentionedbefore by MANY others, he and Sanji have a wonderful contrast of character. I think that the crew needs a "noble" character. One to keep Sanji in check. And also, we dont know alot about him! That leaves all kinds of space for further character development. He has no ties to water 7, other than the Galley La of course, but I think that he would leave water 7 and the galley la if luffy proves himself a worthy captain...and we all know he will. I bet that we get to see some wicked pauly action in the near future.
But...as you all know, the mere fact that we all suspect pauly and franky as potential crew members can almost rule them out as potential crew members! Oda will find a way to surprise us all. I, for one, cannot wait for the end of this arc. It has been the best yet, and isnt slowing down.