That is the point. Simply making Prometheus alone bigger (which also has it's limits and isn't even nearly as large as what Kaido did with Flame Torch), does not mean she would make a Bigger Misery. And even if it did, it's much smaller compared to the Island sized Dragon that Kaidou pulled.
Huh? Your argument makes no sense. Big Mom not making Misery bigger has nothing to do with the limits that were already established in her feats ALREADY. She had always had the feat where her main homies can increase their size surpassing even giants. It is simply Oda plot decision moving forward if we wants to use the feat or not.
2.) You can only argue that with scaling can BM even compete with that size. Scaling argument is weaker then portrayal argument.
The scale of BM's fire when addressed by Jinbei:
The same Jimbei that did this with Ocean Spray:
The only limited that was addressed with that the bigger Prometheus gets the more he loses his nimbleness
Or would you argue King can make an Island sized Karyudon simply because he has shown the ability to change the shape of his Karyudons?
Nope. King has no portrayal to extend the flames to what it has already reached. Your points can't compare.
Invalid was the wrong translation? Fine, he still called her pathetic in an other translation iirc. And that's after taking her on.
His comment has nothing to do with her level of strength so again you're stretching context to be simply make BM look bad for laughs and giggles.
Moot point. Claiming the One Piece came after first claiming the Ancient Weapons to fight the SSG & the Navy. It needs far more manpower than a single Yonkou crew to achieve in the way Kaidou wanted to achieve it.
Please stop ignoring context: