The invisible walls add a cherry on top of the shit sandwich of new maps.
I get it. People complained too much about the horse archers riding off into the sunset, Parthian shooting everyone. Does it warrant every single new and old map to have invisible walls built in to help this? Maybe you could have gotten rid of the nomad wave and been done with it.
"But the walls force people to work together in making a shield wall."
Maybe. But this only works when there's enough shielders to do this.