So I just started watching the movie clip about CIV_5 and noticed some important game options missing from Elemental.
1) Random Personalities -  Elemental has one AI personality for all AI opponents.   Hopefully modding will become available so the community can create the personalities while Stardock fixes the game.
2) One City Challenge -  This would definitely provide a better challenge, but the end game score should be bumped too.  Something so the game remains a one city challenge too would be good.
3) Enable Turn Timer -  Multiplayer can really drag without some turn timer setting.  I can imagine playing a 90min game of Elemental only to have my opponent overseas decide to pause everything during a battle or research screen while he goes out for dinner.  Sure I could exit and then he wins??
4) Resources - We should definitely have a setting where we can decide how many resources are in the world. I'm sure some people want more or less than what's currently provided.
5) Rainfall, SeaLevel, Temperature - Maybe someday when the terrain and oceans are more than just visual.
 
---- Other Game Option Suggestions ----
6)  AI Bonus Units Setting :  Where we can choose for every AI opponent to start with an extra 2 spearman or extra 2 pioneers or an extra 2 champions plus modders could create even more unit bonus settings such as 3 pioneers with 3 maceman  or  2 pioneers with 8 champions.
7)  AI Bonus Sovereign Setting :  Where we can choose a custom sovereign we've created for an AI opponent.  Also allowing us to bump the stats of the AI sovereign with more hitpoints, speed, dexterity, etc., .  It'd be nice if we could fight an AI opponent which wasn't human such as a Troll or Cyclops.
 
{ I will try adding more later... I need to drive into the office today.  }