1-Its not good removing some familiar quests or used features which your previous game has. Of course it is good to remove not used ones. Its good to keep some famous quests like "nervous man" or a liked soundtrack from previous game or a popular dialog.
2-Using town / castle / village scenes for different purposes is more important than we think. Player should spend time there somehow. Its good adding more usage to these scenes which spent tons of efforts. Its good for player to spend time at different parts of game (40% campaign map, 25% settlement scenes, 25% battle scenes, 10% menus).
3-Its so important game should allow different play styles (warrior / trader / roguery). It increases replayibility. Different play styles should be balanced player should not be forced to play same all time.
4-Dialogs are more important than we think. Player should feel himself as a well known lord (if he is lord) or king (if he is king) while playing.
5-Having characters with different personalities is one of the key things otherwise you feel everyone in world same and everthing becomes predictable and it decreases gameplay.
6-Its good giving more control to player, even it is sandbox world leaving player without any control over world is not welcomed. You can hide these things even at dialogs if you do not want them to be easily seen by player.
Its hard to give a full list but these are mostly underlined things. Of course there are more. I see these things already underlined in forums too. These are actually seem like list for M&B series but actually it is not only for M&B. When you analysis these things you get the point what players really want. Even you make a board game you can use these feedbacks to make a better game. Its hard to tell this situation in English (language barrier). Anyway lets stop discussion here because unfortunately we will not be able to give you a record of this QA with subtatle for long time, this post should go down. Sorry for this.