Don't you think Oda is bringing Law back because of the surgery? Law is a competitor of Luffy, he should leave the scene at some point, but he is a character loved by the fans, Oda will not kill him or make him a villain.
No the surgery is important but not most important part of the fruit. To use the weapon that was used in 1060 you need the personality switcher. I think that is what Doffy was hinting about
 
Top