I think many of the problems may be derived directly from Needham himself: an implicit faith in the myth of the apoliticality of science, despite a crisis later in his life which undermines the concept. The gushing eloquence for the "purity" of Needham's love for China. The unspoken categorical implication that technologies are all subsets of science, i.e. applied science. An occasional curious flatness to the earlier history, in which "ancient China" can encompass everything from 300 BCE to 1200 CE in a nearly undifferentiated lump, when usually Winchester is pretty good about including dates. A thoroughly obnoxious line, particularly for Celticists, about how, while the Chinese had already developed sophisticated water engineering methods, people in Western Europe "still coated themselves with woad and did little more than grunt" (109).
Needham did indeed lead a fascinating and well-documented life, such that there were many interludes of which I would have loved to know more. I could see why, for narrative focus, his years spent "putting the 'S' into UNESCO" were glossed over (165), although I'm not sure why only half a sentence was relevant to the original editor of the book series, when the gestation of the series was so much a part of the plot. Even passing mentions, however, helped orient me in some ways, such as explaining Francesca Bray's role in the process of developing Science and Civilization in China, or the foundation of Robinson College.
Overall, I'm really glad I read this book, both for what it taught me about twentieth-century history, and field-specific historiography. It was generally well-written with a compelling narrative, documenting the life of a fascinating individual. As ever, however, it's entirely possible that I could enjoy it so much because I didn't know that much about the central biographical subject. Ignorance is so often bliss.