I do definitely think that AoE4 needs a population limit setting.
I even made a thread about it before release [Poll] Population Limit
Some people modded to game to support a higher population limit already but the game gets unstable and even crashes sometimes when one player has to many units. So it’s not just an easy option they can just add at the moment.
AoE3 moved some of the choice from the lobby host to the map creator. Unlike AoE1/2/3 the isn’t a limited set of different map sizes but instead the hight and width of a map can be set independently with any number of tiles you want. The map size is scripted within the random map script.
Thanks to popular demand AoE3DE has added a large version of every map now. Maybe you should give that a try if that was your main problem with AoE3.
They will release mod tools and a scenario editor for AoE4 soon so we will be able to see how far we can push the game in size and unit numbers before it breaks.
I hope that we can have more flexible map sizes in the AoE4 editor and not just the fixed set like in AoE1/2.
I really hate it that there is no size between Giant and LudiKRIS in AoE2. Some scenarios just need more space then Giant but LudiKRIS is 4x as big and the performance is bad. They really need to add something inbetween. Give us the 1440p of maps please.