Leaders will only make decisions influenced by traits if the trait has influenced the reason for a decision. Example: My trait has reduced my gold. Because my gold is low, I may be more reluctant to found a new city. NOT: My traits tell me to build fewer cities. Leader personalities dictate those kinds of things. Personalities are not traits - they are the xml on the leader itself that can influence what traits are selected if you're playing on developing leaders. The kinds of behavioral differences you point at the Maori as having would be something setup in the personality rather than anything to do with traits.