Why not? You cannot possibly believe that you can faithfully continue a story based on your perception of someone's way of thinking or replicate their personal way of telling a story based on some vague cues they left or told you. Since you know, you were never in their head and no matter how close you are, you are not them.
And even if they precisely told you X will happen in Y situation and Z will die in this particular manner, 100 different people would have 100+ different interpretations on how that should be portrayed.
And what if Miura had changed his mind about the ending between then and his death? We'll never know.