The two Blish works, although loosely linked, differ considerably from each other. The Quincunx Of Time could not, at least not very easily, have become a series. "A Style In Treason" has some parallels with the Flandry series. Simon de Kuyl represents High Earth and opposes the Green Exarchy just as Dominic Flandry represents the Terran Empire and opposes the green Merseians. "Treason" shows us the end of de Kuyl's career so that, if the story had grown into a series about that character, then the additional stories would have had to be set earlier.
I suggested to Blish that, if there was a Green Exarch, then there might also be Exarchs of different colors and he replied that this was a helpful idea. "Exarch" does mean a provincial governor. There was, of course, only one Roidhun of Merseia and Anderson, with apparent effortlessness, wrote many volumes about Flandry's long struggle against the Roidunate. Quality from Blish; quality and quantity from Anderson.