I dont see good idea to back to times when group of bluesuits can take your city without any stuff and you even dont know where to go because they can take few cities at once...
Anyway reason of taking cities is to wait for action, your enemy come and fight or not. Later you got something from it - prices from boxes.You can got all cities and wait 9hours whole day if someone come, then go sleep, wake up and then you dont control anything again

so if you are not online they can take it, but not so easy they must kill some guards - miltia. When you are online you got 15mins to go there and defend it, standing in city because maybe someone come is no sense.
Already miltia arent so good as long time ago, from my experiences about last 10 different actions showed that you can kill enemy even if he s with miltia because almost 3/4 got some spears knife or other shit and about 200hp.
And i hadnt seen in any northern cities full miltia from last weeks ,maybe once.