2.55 SPOILERS:
The thing is I don't think he will be a leader anymore. I just cannot see how he can fill Nanamo's shoes now that he has killed an unarmed man (although he deserved it), he will be known as a killer, and why would a nation want him as their diplomat when he could just snap like before and kill more people. We already know that Pipin opted to go back to Ul'dah, it could be shown in the opening of the DRK quests, that you have to break him out of jail and he then trains us on the way of the DRK, or in the opening CS of Heavenward we might see Pipin getting him out of jail.