"Asher Nasi Yechta", when the Nasi sins (4:22). Rasho brings down the gemara (Horiyos 10b) that says Asher is from "Ashrei", "Ashrei HaDor SheHaNasi Yechta", fortunate is the generation whose Nasi sins. What is so goods about having a Nasi who sins? Is it not a public scandal when he is forced to march in front of the cameras to bring his Korban in the Bais HaMikdash?
The Chida is Midayek in the word Yechta. Chait is an error, a misjudgment. Even the Nasi can make a mistake and his tshuva is a Kiddush Hashem. Unfortunate is the generation whose Nasi is arrogant, that is a Pesha, criminal behavior that will lead to many other aveiros and surely harm the entire nation. When the Nasi is only a Chotei and does tshuva, the generation is very fortunate.
The Iturei Torah brings from Rav Menchem Dovid of Amshinov that a person who is perfect and doesn't know what it means to lose the battle against temptation will not be sympathetic to those who are not perfect. A good leader is one who understands the struggles of the average man. When the Nasi himself tasted chait the generation is fortunate as he has experienced their plight as well and can help lead them towards the golden path.