On the whole, I think she could eventually be a good, even great SecState, based just on her qualities of character. She does have some baggage coming out of the starting gates, though nothing that cannot be overcome.
As a matter of personal style, her stridency makes her the wrong face to put on US public diplomacy. That's absolutely the wrong way the US needs to go on public diplomacy in the near future. "It Can't Be Just About Us"--Frank Schnittger, ETian Extraordinaire