You are quite right. The Miraculous Qur'an can place oceans in a nutshell. It does emphasize Sincerity and Competence as the mandatory qualities of a good leader.
12:55 Joseph replied, "Place in my charge the land resources (the treasury) of the State. I will prove to be a knowledgeable guardian." [Now that he could personally handle the oncoming drought]
28:26 One of the two maidens said, "O My father! Hire him (Moses)! For, the best one you can hire is the competent, the trustworthy."
Hafeez, Aleem, Qawi, Ameen: The four adjectives easily encompass Sincerity & Competence.
You may add Ability, Trustworthiness, Power, Reliability, all of which merge easily into Hafeez, Aleem, Qawi, Ameen.
A lifelong student