I also thought in similar terms, but I did not include my reasoning in the Discussion of the “Geographic” monograph, as it was already loaded with lots of “conjectures”.
A couple of points:
Non-sanguinity (or lack of N trait) is Mendelian dominant, so it means that non-sanguine (NS) types cannot occur sporadically in families, as for example can NA types. If you spot a NS type, you can be sure that he comes from a family where there are other NS types. So, one can see that NS types would naturally form extended families, clans and habitancies (sub-populations)… which is what we do, in fact, observe in the Middle East and in Eastern Europe.
Yes, it would seem that non-sanguine A and PA types would have an obvious relative advantage in territorial disputes (imagine fearless warriors of A types, aided by authoritarian PA strategists). However, paradoxically it has been sanguine and sanguine-aggressive types (mainly N and NA types) who have been the great movers and shakers when it comes to territorial expansion on a grand scale, to wit the Mongol invasions of the Middle Ages, Alexander the Great’s armies, the Roman Empire, the British Empire, Slave trading and the conquest of S. America, Polynesia, etc., etc. In contrast, NS territorial expansion has been relatively modest (although one could argue that non-sanguinity arose very late in the history of modern Homo sapiens). The locales of the Middle East, Eastern Europe and Russia have been fiercely territorial, but it has been mainly regional, with continual border conflicts and expansion by annexation of territory at the borders (e.g., Crimea). Non-sanguine types have not gone on gallant marches of territorial expansion, and even the possible NS core of Islam has expanded over the centuries by persistent gradualism.