However, the most notable change is now you have the chance of coming across 4 new races in some expanded territories to the south and to the west. The faction you play will behave 95% identical to how they did before.
Your lord or race will start in the same place, their mechanics will be the same, their quests, buildings, units, skills and objectives will largely be the same, there are some slight variations to one or two technologies or events here and there, certainly not something that changes the playthrough that much. However the mortal empires campaign, if you’re playing as one of the old races is basically a mirror copy to the old game.