I hate to rain on the Kennedy parade, but I think Robert Kennedy would have been a poor president.
The record shows that by the late 1960s, Kennedy was strongly wedded to liberal ideas about the role of government that have proven in the years since to have been a miserable failure.
All the charisma in the world can't change that. I agree that RFK was somewhat better than some of the other liberals who followed him, but that's not saying much.
I think you underestimate how a Robert Kennedy Administration could have dealt with the trials of the late 1970’s or early 1980’s. Unlike Teddy and like Jack he was a pragmatist and interested far more in what worked and what was practical than what might seem ideologically pure, sure he was in values very much like LBJ or Teddy but in his implementation of these I think you would have seen polices not dissimilar to the leftwing in Australia “monetarism with a human face”
spending cuts and more progressive, yet far reaching tax cuts and a hawkish foreign policy.