Current main scenario (story) / quest  much like keep doing killing monster quests,

some thoughts for next Elemental game are

Bland in city building aspect

1) have some requirement to train X number of Y units for some reasons

2) To build X number of improvement in city or a specific improvement X 

3) To have all city connected by roads

4) To have a city in level X

Bland in Sovereign aspect 

1) To get a Sovereign in level X 

2) To get X number of sovereign

 Bland in some research / magic aspect

1) To research  technology X  

2) To cast spell X  

I think this at least can increase  a lot of variety in quests / scenarios