According to the Qur'an, only two basic qualities are required in a great leader: SINCERITY & COMPETENCE.
JOSEPH: 12:55 Joseph replied,"Place in my charge the land resources (the treasury) of the State. I will prove to be a (HAFEEZUN ALEEM) knowledgeable guardian." [Now that he could personally handle the coming drought. 28:26]
MOSES: 28:26 One of the two maidens said, "O My father! Hire him! For, the best one you can hire is (QAVEEUL AMEEN) the competent, the trustworthy." [Competence and trustworthiness are the essential prerequisites for a responsible job. 12:55]