A great article all around; can't wait for the next one! The points and questions raised here bring to mind the relatively unexplored (as far as I know) subgenre of AH revolving around geological/geographic divergences; the only two I know of for certain are Turtledove's Down in the Bottomlands (where the Atlantic did not reflood the Mediterranean, leaving the latter as virtually desert) and Atlantis trilogy (where the Eastern Seaboard broke away to form an eighth continent of that name). I'm curious what your thoughts are on this subgenre (and the above books, if you've read them), and if there are any other books or articles you would recommend that build on Gould's work.
I'm also curious as to whether your series will consider the issue of specific resources within geography (Ex: the lack of or abundance of oil, coal, timber, arable soil of various kinds) and how such might play a role in AH. I'm tinkering with a rough story idea along these lines, and any thoughts/suggestions would be welcome: the TL is one where no oil deposits were ever formed, and so human civilization has followed different paths of development around the prolonged use of older resources such as coal, or the discovery of new ones (as yet undetermined).