Diable jambe never changed Sanji's fighting style, it actually added on several character traits and strengths. Fire adds a new nomenclature of culinary-based attacks (since fire is the representative element for cooking), fire represents his burning passion of an emotional man, the DJ also adds in the visual elegance of his kicks which is perhaps the most striking features, outstanding in Sanji's fighting style.
Diable jambe completes Sanji, that's why you've never seen any fan complain about this PU.
Meanwhile, the RS adds robotic/technological materials that don't match his fighting style, his power-ranger look also doesn't match his design of an elegant, flirtatious, gentleman cook.
Not only that, but the powers of the RS disqualify many techniques that Sanji learned himself, I've already mentioned why in another topic:
I see all the traits that made Sanji such a unique character being completely destroyed if RS really remains. Many of his values and virtues that came from Zeff, like his martial art, will be radically changed by cheap technological materials. Many traits that have been written throughout history that have made Sanji a character that I and a lot of people have come to like will be replaced by the power-ranger style.
I won't stop liking Sanji, but I will like it a lot less if the RS isn't destroyed or discarded during the fight.
Diable jambe completes Sanji, that's why you've never seen any fan complain about this PU.
Meanwhile, the RS adds robotic/technological materials that don't match his fighting style, his power-ranger look also doesn't match his design of an elegant, flirtatious, gentleman cook.
Not only that, but the powers of the RS disqualify many techniques that Sanji learned himself, I've already mentioned why in another topic:
I see all the traits that made Sanji such a unique character being completely destroyed if RS really remains. Many of his values and virtues that came from Zeff, like his martial art, will be radically changed by cheap technological materials. Many traits that have been written throughout history that have made Sanji a character that I and a lot of people have come to like will be replaced by the power-ranger style.
I won't stop liking Sanji, but I will like it a lot less if the RS isn't destroyed or discarded during the fight.
Sky Walk can likely be used in conjunction with his boots for more efficiency otherwise Oda wouldn't have decided to give him both, he must know what he's doing. Arguing against it because it seems to make no sense would be like arguing against Blue Walk because there's no air Sanji can use underwater. There's Sky Walk, there's Blue Walk and there will likely be a third version of the technique, Sonic Walk or whatever.
My only gripe about the RS is that it's a power up handed to him by his despicable family. It represents everything he hates and Sanji relying on it is a poor decision in terms of storytelling, as he should become stronger on his own to prove his father wrong. Oda makes it a matter of pride and shows the importance of swallowing it for the sake of protecting people, but it should be more a matter of moral sense and philosophy than a matter of pride.