Map scemes for multiplayer
So I checked out all the multiplayer maps KaM remake has. Turned out nearle all the maps feature 1-2 chokepoints per player. If you tower those up, the opponent cant gain anything from attacking you, since he will lose more troops. So its world war 1 situation and its useful to just sit there. I drew a bunch of scemes to explain some basic ideas that some maps miss in my opinion:
Number of chokepoints

The colored spots mark starting locations. The black areas are unpassable. White areas are passable. On the left colum are 2 player maps, on the right corresponding 4 or 8 player maps.
For map number 1, theres absolutley nothing to do for any player. However, if you make 4 player map like that, you might get away cause people wont notice. Someone did as we can see in the current map pool of remake

For map number 2, there is 1 choice, which is already gazillion times better. However its usually still realistic to just tower both chokepoints and move your crossbows between the two as needed. Vast majority of the current maps are like number 1 or 2.
For map number 3, you actually DO have a choice. It's much harder to tower up all 3 spots fast and move armies between all 3 spots. For instance you can tower 1 spot heavily and bounce army between 2 other spots. The 3rd sceme on the right reminds of good examples like Land of Hills, Road of the Valley and Warfare in the Wilderness.
The size of "chokepoints"

Ignore the right-most map for now. Which of the two remaining maps do you want to use cavalry vs enemy archers? If the chokepoints are very tight and long, you cant counter archers. If the chokepoints are wide and short, you can counter archers or at least maneuver a little bit. They are not even real chokepoints anymore. On the right there is middle map + some terrain, since there has to be rock, iron and gold somewhere.
Bouncing between the chokepoints

The map on the right has very different "army bouncing distance" for players. Blue has to move long distance from one chokepoint to other, while red can defend both chokepoints with same army. Thus red can defend his base more easily. The map on the left has nearly equal army bouncing distance and is thus more balanced in this sense.
Terrain favouring certain units

Good thing to ask yourself is, what units would I make on this map? Here are 3 extreme examples. The distribution of passable and unpassable terrain alone makes it very clear, which units you need. If you only need 1 type of units, EVEN in KaM, its not very good. In case it isn't obvious:
1: mass ranged from one edge of the map to other. Nothing to do with cavalry.
2. Mass ranged since you shoot over the rocks.
3. Mass cavarly since the map is huge and no chokepoints. => make pikemen since enemy makes cavalry
Where will the battle occure?

2vs2 on map Kaderto. Red team has towns in red circles and towers up chokepoints that have red X. Same for blue team. Where will the battle occure now? The upper and lower bridges are longer and more narrow than the middle one. It's very hard to make any progress there. Thus all hopes are on the middle, unless someone makes stupid things. Red team cannot tower up middle chokepoint fast enough while the blue team can.
The area surrounded by yellow circle is also very easily defended by red teams crossbowmen but this is still pretty much the best place to attack. But its still pretty bad. And what will blue gain from attacking? Will he go for the iron and coal there OR will he mass farms and leather troops on his massive free land, that is 100% safe? There is nothing to gain and making progress only leads to loss. Thus battle will not occure.
Where will the battle occure, part II

Alternative map: red team towers up, blue team towers up. Both have at least 3 chokepoints to defend and these are rather wide. Yellow areas mark "booty", like iron, gold, coal. Fish maybe

It might happen that one of the teams goes for top right corner booty, so there will be fighting there. The central booty is wide open to attack from all directions. Even if you erect a few towers there its still not totally defended. There's also very little space in the starting area, so you have to push out (which some maps have accomplished very nicely, cant remember names). All in all, there are things to gain, you cant tower them up and there will be battles.