What if Neito Monoma of class 1B replaced Rikidou Satou of class 1A?

Well, if Neito Monoma of class 1B replaced Rikidou Satou of Class 1A then something interesting results we can will see within the class dynamics and also the story of My Hero Academia.

As from starting, Monoma has completely different personality and skill from Rikidou Satou, whereas Satou is good in his physical strength and also proficiency in hand-to-hand combat, Monoma has a quirk called Copy but it's gives him temporary copy and use the quirks of other individual which give him a unique advantage in battles and challenges.

Monoma's desire to prove himself and natural being may be create tension and rivalry within class 1A. While, Satou's peace mind personality and team player mentality would be missed here.

Overall my conclusion is that it's little bit hard to predict what exactly the story will change with this replacement, but it's most probability that there would be some interesting new dynamics and challenges introduced to the class and the plot of My Hero Academia.