Mostly this.
I don't really want to join/initiate the panel/balloon fight and start posting the spear speech from the Baratie, the times Sanji acted as the leader of various groups and so on. He also showed the power to turn into allies multiple people on his paths, just like Luffy.
ACoC is just AACoA, I doubt CL²⁴Oda will go out of his way and give Sanji a unique power to damage immortals
unless that power was also deeply intertwined with the main plot (e.g., Sanji merging with the Mother Flame).
One thing is certain: Zoro fans should dread CoCless Sanji the most. We all know Sanji will be able to hurt HK/Gorosei sooner or later. Judge acting on his lineage factor and Sora willingly sacrificing herself made Sanji the human (?) he is. Anything coming from those deliberate actions would be much more meaningful (and more unique) than being lucky enough to be Ryuma descendant. Not that they care anymore, a normal guy training to overcome his limits is old news