In Avengers 688, they mention that Sunspot if it is not contained is the strongest mutant on earth? Seriously, it seems that you forget that there are at least 3 class 100 +++ that are mutants, and they are class 100 in their normal state.
I do not consider it a bad writing, since the one who said that he is the strongest mutant, was nobody but Roberto himself, and we all know how he is.
Roberto is not a class 100, and when he unleashes his power, I do not believe that he will become a class 100, since there are several mutants that are above him.
In fact, the most powerful physical mutant is between Rogue and Namor.
Rogue Namor >> Gentle> Colossus> Frenzy> Strong Guy> and already after this it is debatable if Sunspot comes.
What do you think?