I think an important issue in this generalist/specialist debate and this attempt to create a list of the most important figures is that the historical time frame may be very relevant.

As the world becomes increasingly complex and fields of study, old and new, become increasingly specialized, would this not affect the ability of a generalist/specialist to produce a significant insight or make a significant contribution?

Perhaps it makes more sense to consider much more recent people as examples if we want to apply this to society as it stands now.