I think it's funny we think we can pick-and-choose. "If only Patton had been just as great but less of an asshole". What if that was an important part of making him the great leader he was? Traditionally negative traits can sometimes contribute to effective leadership.

the slapping incidents were an example to Eisenhower, Marshall, and other leaders of Patton's brashness and impulsiveness

His most successful and famous campaigns can be described as brash and impulsive!