I have a few things I would like to see implemented into Elemental. Here they are.

1. Rebellions- I would like to see some kind of unrest modifier tied mainly to food, and (if possible) cultural majority. I wonder is there a limit to number of factions? I could see the 10 main kingdoms and empires but then I would like a variety of minor factions like city states (that can expand thier one city as big as they want, but not build pioneers.) bandit, knight, monster, orc, goblin factions, witches, rouge powerful wizzards that can be bought (maybe quested) that could "come out of the woods" claim a city and turn into a full blown faction.
2. Hidden in the forests+more forests- Maybe a unit like "Guardian of the forrest" that changes tiles to forest. Also I would like to see limited visibility to forests even in your territory. Were forests reduce your visibility to just one.
3. Farms - Farms to the outlying squares. Farms shouldnt just be one square covering fertile land. Maybe have the one in city food square call it garden, etc and that would help balance your food loss if lets say an army burned all your other farms. The farms should surround your city and be on the boundaries of your border. Bandits and monsters would raid your farm and it would be up to you to keep your food coming in or risk rebellion (due to no food). I also would like to see food storage (a percentage) stored for famine, winter etc. I think this would add a whole level of complexity and fun to the cities.
4. Catastrophy - weather mainly harsh harsh winters (think ice and fire) Civ has implemented code that changes terrian squares in cycle. Winter comes you loose alot of your food production and you have to survive by your storage of food etc.
5. Hoards- Others, monguls, bandits, orcs, giants etc. I was thinking Others a powerful unit spawns and generates a additional unit every 3-5 turns. You can stop it, or if its not delt with it turns into a huge problem that gobbles everything in its paths. Maybe tie troll, orc, giants into the first idea were they could found thier own kingdoms.
6. Fortifications - Not sure how these work now but maybe make fortifications high until an initial breech. Once they are breeched have them have a reduced rate. Then cost the defender on repairing the breech.

Just a few ideas I have to make the game more fun and fleshed out.