I know the number of open gates that triggers the awakening of the Ancient One reduces as the number of players increase, and the number of roaming monsters in Arkham increases as well, so there is the crowdedness factor that seems more perilous. Also, there are two monsters per gate opening when there are 5+ investigators. Are there other factors? These factors don't seem as significant or maybe as linearly ramped as the balancing factors in Eldritch Horror where clues, gates, surges, and mystery requirements scale with every 2 added investigators.