That was a shock. I only read one of the 1632 books just recently when I realised I had bought some of the later ones a few years ago and never got around to reading them.
Flint definitely changed the genre and brought in a whole new audience - and a whole new set of writers, for that matter. The 1632 phenomenon came at just the right time in the early internet to become a collaborative project unlike anything seen before or since. I remember when I was a student sending some of the supplementary material written by 17th century experts to my History & Philosophy of Science lecturer and her being surprised that stuff that she had considered so niche was now coming to a modern, fairly mainstream audience. He broadened the Baen label beyond its stereotype of right-wing military science fiction to something truly remarkable.