I’m not so sure that books that have embarrassing stories of gedolim should be written, though I agree that just about every biography is written in the same way, with the same superlative descriptions.
Just about the only biography I ever enjoyed is about Rabbi Shlomo Freifeld. The book doesn’t go on and on ranting about how smart he is. Though it gives clear examples of his amazing and worldly wisdom, that will teach any person how to be a mensch and put a head on their shoulders.