[OPINION]
To start off i just wanna say that im kinda dissapointed.
Here's why..
Marco, Sengoku, Devon, Orochi, Kaido, Yamato, they're all among those mythical zoan type DF user, and they're all (by far) represent creatures, higher-being or entity from many beliefs/cultures around the world. The idea to add "mythical" into Zoan is actually kinda dope, dont get me wrong.
Until in chapter 1044 when Luffy's DF finally revealed. I was really excited when the Gorossei said that its actually mythical zoan type, because I cant wait to find out what creature is Luffy gonna based on (the only thing that comes in my head is Wukong) but then the model was revealed and it turns out to be Nika.
When i read all of those explanation that Gorossei said i was like "uhhh what?"
Lets break it down,
First thing first, I cant be the only one who thought that mythical zoan model is based on real-life myths (Marco:Phoenix, Sengoku:Buddha, Devon:Kyuubi, Kaido:Azure Dragon, u got the point).
Oda is seems like took reference from those real-life myths/urban legend and apply it into OP universe, which like i said, its dope. So the whole idea of a mythical zoan is : its basically a zoan but much more rare and powerful, because its resembles myths creature, which is of course, they're rare.
And now, Nika...
Who/what is Nika exactly? what so "mythical" about it? theres no reference to this exact name, on my last post people said that its a myth that only exist in OP universe, if that so, then the whole idea of mythical zoan itself is ruined. Theres no other character (by far) who has a mythical zoan DF is based only from Oda's head, they're all exist irl.
In my opinion...
It seems like Oda is kinda ran out of ideas (probably) to buff Luffy's power along with all of the available enemies left, I mean he's just a rubber, and its actually very impressive for Oda to push it this far into Gear 4 and make some of us still buying it, i give him that. Or maybe he's just simply cant find any mythical creatures out there which represent rubber, so he decided to make his own fictional thing, because he need to buff Luffy no matter what to keep the story going.
And now? there it is ladies and gentlemen, the one and only mythical, i mean, fictional zoan model...
The almighty Nika, the Sun God, who instead of having the power of the sun, it holds the power of imagination, and has a rubber-like body, why is it called the Sun God then? Idk, is it really that necessary for a Sun God to have a rubber-like body? Logic screwed.