Adding more personalities may change the diplomatic atmosphere . With so many playing more than 8 civ this might be something to look at.
In the Alexander The Great scenario there are 11 personalities 2 more than the main game .Also changes in the- Civization Text file in Game Data !
In three of the personalities that have for Discovery:Military in the next line Conquest:1Passive
In the main game 6 out of 9 personalities are Agressive . In ATG scenario 6 out 11 are Agressive
Conquest: sets the Ai to resovle disputes through war or diplomacy--- Passive Neutral Agressive
Maybe someone like Dale or others could find the right mix for more personalities Also dont know how the computor picks the personalities for each game level