Well… During Neolithic shovels were made with a cow shoulder blade and a wooden handle, so no aggers. And when considering that for most of the base game you probably will have a maximum of 100 or 200 people in your settlement, this means you won’t have the workforce necessary to really siege a village.
If I remember correctly, horses and chariots only appeared at the very end of the period, with the Indo-Europeans.
But that’s the “beauty” of it all. Every people lost in a raid (either as defender or attacker) will be a true economical drama because every one of them should be a scare resource, that you should have to compensate one way or another to don’t impede your development.
And this means also every fight, involving at most a few dozens of people in each camp will be stressful as hell.
And, last point: even if this may seem dull if you’re essentially interested with warfare, the DLCs coming after the basic game should progressively show more and more people relying on more advanced technologies, meaning also the appearance of real armies, at first as a few real professional warriors (be they bodyguards or every name seeming appropriate) then later as more organized corps.
700 Años de Artillería Evolución histórica de los materiales de artillería y sus municionesPor: Coronel de Artillería Don Antonio de Sousa y Francisco Museo del Ejército, Madrid, EspañaEl coronel Sousa y Francisco estuvo destinado en el Museo del Ejército de Madrid y es hoy Director del Museo Militar de Melilla.