In every RPG all the characters are fixed and you are forced to play with them e.g. in the beginning you don't have every character unlocked so you have to make do with what you got. So really what your doing is contradicting yourself, since every RPG I played you have a choice of let say 3 characters after a certain point you get a new character unlocked. It's a take on that concept and I don't know why that's a problem.
"Life is but a gentle death. Fate is but a sickness that results in extinction and in the midst of all the uncertainty, lies resolve."