Timeline-191 is always interesting idea for mod, but, why using that complicated E3 map?
It adds much more complications to the creation process then it gives benefits.
As I remember earlier attempts to make Timeline-191 mod also used E3 map and failed, partially due to complicated creation process caused by map.
As far as I'm concerned, mainly to keep the combat more dynamic, discourage AI deathstacking, and some more flavor, and so on.