"How will the American women's 4 x 100m WR affect middle distance runners?"
The women's 400m and 800m WR's are squarely in the category of records that are affected by the new mentality. Although the 400m is most often considered a long sprint, some consider it a middle distance, especially for the women; and everybody considers the 800m middle distance.
Likewise the 1500m. Have you looked at the top 10 for women? The dates vary from 1980-1997, and among the athletes is 1 Romanian in Seoul, 2 Russians in the early 80's, and 7 Chinese, including the top 4, and the WR.
Nobody is yet closing in on the 1500m, however, as they are in the 100 and 200--the best recent performance is Selsouli in 16th place, 5.5 seconds back. A bit further is the Ethiopian Aregawi, followed by the turk Alptekin, in 21st and 22nd places respectively. Judging by the dates of the other top performances on the list, 2012 was a hopeful year, with Dibaba on the list as well.
What I don't know is whether or not Chinese records can be equated to East German/US records, for the purposes of hopefulness coming from the women's 4x100 WR. The US and east euro records were obviously steroid-fueled, and have been proven accessible by both the 4x100 and by Jeter individually--but what of the Chinese records? What exactly were they using, and can it be approximated by anything available today? I don't know.
I guess the good news is that if not the 1500m, then the 800m should be considered accessible.
And Drummond? Yes, it appears that he has done an excellent job with the personnel with whom he worked. Like I said, look for him to be dismissed soon.
He did a particularly good job handling that pain-in-the-ass Tarmoh.