For me the history of AoW is a long story of minimazation of exploiting flying units over AI. In AoW humans' Air Ships would eliminate everything just kill archers before. Or dragon would breath out the whole army. It was not hard to do. In AoW 2 and then SM it was minimized weakened ballista for Air Ship limited breaths for dragons. But inability to take the flyers down without ranged attack still was very huge advantage for flyers. And finally every unit ended up to be on the ground.