Just out of curiosity where did this quote come from?"yang has no real power, he is one hundred miles away from China's inner power circle"
Although Yang Jiechi isn't exactly the face of China's foreign affairs, he does sit on the Politburo while Wang Yi as Foreign Minister is "merely" a member of the ~300-man Central Committee... and well the 25-man Politburo (a level above the Central Committee) is only a level below the 7-man Standing Committee, which is the top decision making body of the country. In other words Yang is very much in the inner power circle of the party. He is a friend of the Bush family, has extensive experience as Ambassador to the US, and Xi Jinping clearly values his counsel as well as his insight of the West to bring him up to the Politburo once his term as Foreign Minister was up in 2017.
I highly doubt the conversation ended in any sort of constructive change/difference, however it is imperative that both sides keep the dialogue going despite our differences in order to prevent a cold war from going hot.then why bother to call?