Ra's Al Ghul was Thanos before there was Thanos (well, in movies, at least). A sympathetic baddie that is deluded by his distorted belief in balance being the crucial accompaniment in society. But, Ra's was better, because we got to know his human side before we got know his villainous side. That's why the twist with him works so well. Its point is not to wow us with how unexpected it is but to distract us and let us comprehend Ra's's human side before we know his villainous side.