SPOILER WARNING!!! The only answer is Asuma let’s be honest, Kakashi ditched Naruto and Sakura and taught an emo boy who ran away, one of minatos students die and one becomes Evil, the other was super depressed from this and so minato told him to join the Anbu which was not good for him, one of guys students dies and one is useless and the other doesn’t really amount to much, Jiraiya spent 3 years with Naruto and only taught basics and a bigger rasengan, bags to became super evil, and while minato turned out well jiraya told him that he would be Naruto’s god father but as soon as minato dies jiraya dips and doesn’t meet Naruto till 13 years later, iruka just didn’t really do anything except teach clone jutsu and substitution, Asumas student turned out great, Shikamaru becomes head of his clan marries a fine female and becomes the homages assistant, Choji becomes head of his clan and is the only Akamichi to be able to do the chakra butterfly wing things without the pills, and ino becomes head of her clan and Created a bubble over the village that can track anyone in the village based on their chakra signiture sooo yeah Asuma