Specialize Champions as City Governors Instead Than Warriors (new buildings can improve traits)
In the Total War games champions (called generals in that game) by spending time inside a cituy gain attributes that specialize them as governors better traits are acquired in those cities with specific schools bad traits are acquired when spending too much time in rural cities or in cities very far from the civilized world. Because of the mechanics of this game I suggest a similar situation, where the champions could be specialized as governors by making them study specific traits once they spend time in cities with specific guilds or academies, but maybe they could also buy items that give them certain skills (imroving maybe those attitudes that they already have) That could also allow to gain more tech points without the need to spam cities, and would allow the creation of new buildings.