maps with random player placement use a clustering algorithm to divide spawning position between teams, so, if you make yourself a lot of enemy AIs in one team, you will not spawn in the middle of them, but on one side.
make it a small map and you will have the chance to start immediately to harass and dominate the neighboring AIs while also having to prepare for attacks from further AIs.
This will make for a game full of action.
Another problem is that call to arms lets the units target buildings. It can be additional work to switch the army to "attack move, units only" after using call to arms.