Upon further consideration...
A huge multi-player game probably won't work, but that doesn't mean we can't somehow manage a huge game with players controlling the Civs. Reading other comments this might be doable but you will simultaneously have to scale it up and scale it back. The sucky starting position might not be that big of a deal as some people like the challenge, and human diplomacy means alliances can keep even a bad start in the game. Now it's just a matter of managing how to run the game itself.
Here are some ideas;
One person runs the game, everyone else tells him what to do.
* No barbarians, all civs have vision, no city-state, turn limit and probably no diplomatic victory
* The game will be broken up into 10 turn blocks. A single person will get designated the 'Game Master' who will play each turn on behalf of the teams.
* The game master will one run block of turns a day.
* Each team provides the 'Game Master' instructions on what to do for that civ in the next 10 turns. The game master will follow those instructions as closely as possible.
* At the end of each turn the game master uploads the save file and the players decide what to do turn the next block.
* All orders are kept secrete between the game master and teams.
Need to limit what the players can control to keep this from getting really unwieldy. Instructions to the game master include
* What each city should produce next. You can only change production at the beginning of a block.
* What you should select as your next research
* Which religious tenants to found. If unavailable then you save the prophet until the next block.
* Which archaeological site to dig. If someone beats you too it then they move as close as possible to the site and watch until the next block.
* Which tile work boats should improve.
* With the exception of building roads workers are always automated.
* What to purchase with gold. All purchases are done at the start of the block.
* World congress delegates.
* What to do with your great people.
* Trade routs to establish.
* Governors always control which tiles the city population works. You can decide specialists, focus and avoid growth, but you can't micro the city tiles.
* Exploration is always automated.
* Teams work out their trade deals offline. Both civs must have the trade deal in their orders, and if they do not match up it doesn't happen. If you can't do the deal exactly as stated(i.e. they don't actually have enough GpT because of a sudden DoW) then the deal is off.
* If a unit is scheduled to be built a non-combat order may be given unless it's going to actively be in combat right away(see below)
* Non-Combat movement is order by identity units and general location to move. Options include friendly cities, neutral cities, or reinforce the front lines.
If it's a friendly city they will march inside the cities borders and garrison if possible.
If it's an enemy or neutral city then they will march to within two spaces of that city and go on alert.
If it's a reinforce action they will march towards the active combat specified.
So a typical order would be "March 3 legionnaires and two archers to the mountains SE of Carthage". The Game master will attempt to get units as close as possible, but will not give any special consideration to troop position or micro management. Units that can't make it because of changing situations that block it's path get left behind and catch up when they can.
For now lets assume one civ vs. one civ. If we can figure this out we can grow it to include multi-civ combats.
* No sneak attacks. All attacks must be proceeded by a formal declaration of war. The DoW is processed on the last turn of the block.
* Upon receiving a DoW the players involved will download the save file from the game master and create their own pitboss game to process their war for the next 10 turns.
* During the special pitboss game players may ONLY control military units that are actively involved in combat. Actively involved means units that are within 3 turns of movement from an enemy unit or city border. If a unit would add +1 to the turns if they would move completely inside it's own borders(i.e. defenders can pull from further away) Note that this means that the units actively involved may change based on the flow of battle.
* During the first turn after a DoW the players are allowed to use a map editor to set up their army formations. They may only reposition units that are actively involved in combat(see above). The attacker sets their formation first, followed by the defender. They are allowed to use two turns of movement worth of distance to instantly reposition the units using a map editor. However, this may not end up with a unit closer to an enemy city than it was before. (i.e. lateral moves or swaps...no using this move to get closer to the city). Units that are completely within their own borders get another 'turn' of movement distance (i.e. defenders can reposition more).
* Players proceed for 10 turns only controlling the units in combat. At the end of 10 turns they will provide the save file to the game master.
* The game master will use a map editor and manually update the master save file with the results of the combat.