beetle, I don't think the described pattern of seven hexes actually tessellate. Every change in scale is meaningful; it increases the granularity of the game, making the "rounding" of path distances less and less, for instance. But it does grow the game size polynomially.
You asked, can players issue commands simultaneously? ... yes, they can. Inasmuch as anything in computing is simultaneous.
But your question wasn't technical (or, was it?) Yes, you can design the game so that different players enter their orders simultaneously. What they can't do is -perform- their actions simultaneously, because that's not a turn based game anymore. That's starcraft with awful response time.
I agree that Civilization could potentially be made into a non turn based game. How?
Easy,
Turn 1 (4000 BC):
All the players in the game (Human and AI) start the game right after the globe is generated.
There are specific game periods, each of them allocating a specific time-in minutes/seconds- period, allowable for your action(s), for example:
The first period , for example, 60 seconds, is solemnly dedicated to unit movement, engagements, tile improvements, etc. While in unit movement/engagement mode you cannot access any other screens, you just have to move/engage, settle, improve with your existing units.
Then, after all civs in the game have finished their unit movement sequence the second sequence comes around: City Building. This would include building queues in the cities, let's say 2 min max allowable for all cities.
After every civ is done with that then you get the prompt for other civ actions-the 3rd part of a turn, which would include your interactions with other civs and other aspects of the game, another 60 secs..
After that the game would go on, without prompting you to start a new turn, dates going forward on their own.
As the game progresses it would increase the maximum allowable time for each movement period due to expansion.
What do you all think?
It needs refinement on the tail end of those phases. I think any finite amount of time for "diplo between players" is not sufficient, for a plethora of reasons.
Firstly, you ought to be able to communicate as much as possible, because arrangements can be quite complicated. The computer player can't understand outside of the trade screen, but players can actually arrange World Congress blocs, agree on unsettled territory, plan warfare, ... a million things.
Secondly, even sticking to trade screen stuff, there is an issue of initiative. This is a part of the game where he who acts last may have the advantage. Or he who jumps in, has given away some information (e.g., his desperation). Thus, for any amount of time you give, in a freeform arrangement, there will be players who wait until the last X seconds, and then make deals. But if you hogtie them with a prearranged sequence that's moving backwards too. Again, a hybrid arrangement is very fashionable. Players should be able to propose any deal, or declare that they are "done". Now, people are gonna want to pad that period of time with some 'fake' dealmaking, sure, so what the engine should do is threefold:
Not actually tell other players who has clicked "done" (this may have to be lifted for reasons*)
Continually allow dealmaking as long as deals are being made (proposals, counterproposals, or accepted arrangements are sent). If no one says -anything- for , say, 10 seconds, but not everyone has said "done", then a backup system kicks in to force everyone to make their final arrangements. If the last thing to occur was an -accepted- deal, pad the grace period by a bit more, to allow those players to process their change in resources.
Force players to make their arrangements. A weak system would be doing it in a preset order. I think better would be, again, desynchronizing it. First the engine tables all floating proposals. Then you enter deal proposals in a strict period of time. Then all proposed deals are sent. I guess at this stage you should only be allowed to accept or not accept; counterproposal chains shouldn't be rushed, plus you've had the whole time to negotiate in chat.
While we're on the subject of chat, please embed an in-context chat system that broadcasts to all met players, or all players who are designed to be able to see things you do. I.e., anyone who can see "[You] and [ThatGuy] are now friends!" should be an actual chat option, which sends your message, and a signature from the game proving that the message was sent to all and only everyone who met you.
I like the timer keeping up with expansion. Notice though, that this shares information about whatever the timer is based on, with all players. So by design, the demographics screen must be intended to also tell you the same information; whether it's "total standing armed units in the world" or "settled territory" or whatever.