I fill like the line of sight think in warhammer total war was more link with maps than engine. It was less an issue in Empire, Napoleon or Fall of the Samurai. Since, they added “smog”, and the need to not flat terrain … and the dumbziness of direct hit unit. With modern building, it should not be an issue.
I do relate on the tempo; I couldn’t imagine how to deal with thousands SM engaging at the same time. I’d rather smallest and intense fight (like in DoW II or World in Conflict), or a way to program actions and reactions of units. I do not see how it would be feasible with the mechanics they made.
However, their making for Three Kingdoms were brilliant, so maybe …
Total War: Warhammer 40k (youtu.be) angielski
Praise the Emperor!...