Yeah we still don't know how he can superheat his kick. Originally Sanji was gonna have invisibility ability hence stealth black, however the drug kicked in. He still got exoskeleton but without losing his other aspects unlike his brothers.
His diable/ifrit jambe is probably never going to be thoroughly explained like Asura and overall devil fruits. It's just his passion burning to a great degree as long as it wont fuck over his body. We know Asura had something to do eith CoC but Zoro didn't even know he had it when performing it, why can't other CoC users manifest then the spirits, it adds many more questions I doubt they get answered fully.
Or devil fruits being miracles or wishes or strong desires manifested from humankind
I don't disagree with the things you wrote when i don't think that oda will fu#k us all. Lol.
I have a theory that both zoro and sanji will awaken a df from their will.
Their desire to protect what is important for them awaken superpowers that their body wasn't strong enough to handle at the beginning.
Zoro never stayed in ashura for too long and sanji confirmed that he can use hotter fire now that he is tougher/more durable.
All this go to garbage when i start thinking about Luffy the MC that just have awakening and his df make him a God.
It's this thing that makes me believe that sanji is a science product and zoro has something fishy as well.
If the MC get a super free pu the other top two will have the same treatment.
In that way every fanbase can troll the other equally
