Let’s come up with new “war machines.”

Guys, you completely missed the point of the question. Besides tents, ballistae, and carts, we need to come up with a unique combat machine for each faction. For example, a dome that grants 30% magic resistance to selected magic units. Or a siege wall that protects its units from Haven archers. Or some special dendroids for Sylvan. Or a seismic machine for the demons...