Hello everyone, this will be a very long topic so take your time.
Whenever I play games like that in multiplayer I usually love playing in teams (or things like me in a team with my friend and the difficulty set really high to balance that) and i know i'm not the only one to make that kind of team play, for this topic i'll compare mostly of the mecanics with the one that are used in civilization 6, so:

1.CLOSE SPAWN:   it will be geat is, as in civ6, you can prebuild a team with another civilization but in civ6 there are a really big problem, you cannot chose to spawn close to your team, and to be honest me and other communities when we are talking about that this is a really big problem that makes you reset and reset the game untill you find a close spot between you and your team, it will be great in the humankind team system for all of us to be able to at least set (or making it obligatory because after all you are playing in a team) to spawn close to your team (i don't mean like 2 blocks close, but at least 5 or 10)

2.SHARED DUST CONTRACT:  a shered money (aham, dust*) system, so you don't have to make a contract anytime another player needs your dust for something, you are in a team after all so a contract of "shared dust for 30 turns" for example where all the players share their dust per turn and total money will be a really nice add

3.GIFTING UNITS: (this is not a function only for teams) why you can gift entire cities to other civilizations but not a warrior or a builder or a settler? or demand/buy them from others? it will be a very good strategic point if you think about it, let's say you need a builder and you need it fast so you have to buy one, it costs 350 dust but you se (for example) the roman empire with 3 or 5 builders so you think "what if i buy one from him for 200? he have a better economy than me so for him a builder is cheeper, it will be a profit for both of us"

4.PING SYSTEM: even if you are teaming up with an IA or a Player you shoud be able to at least ping your intentions to the other, like in endless space 2 where you coud ping to your alliance what system you want to attack or if you need defence for one of your systems, as a team/alliance i think is necessary to know what the other wants to do with his units or what are his intention before even it start to prepare a strategy so you can work together

5. POLITICAL BONUSES: by political bonuses i mean that if all your team respect the same political structure (for example in a team of 3 all the 3 civilizations have a democratic system) all of you gain a little bonus in cultural points and maybe even fame points by doing that. after all it will didn't make much sense a team with totally different style of goverment 
and by pointing that out, if you have fascism and the other civilization of your squad have a democratic system maybe even a penalty for that will be very nice, because i don't think that as a citizen living in UK you will be pleased by knowing your city just made an alliance with north korea for example

Being a team does not mean that it have to be all wanderfull, there is a need for some penalties if you are not playing in harmony with your team too like point 5., saying that, for now i don't know other kind of penaltyes you can get by playing as a team so if you have some ideeals let's talk about it here, and if you want to debate or comment one of those 5 aspects, mantion direcly about that point you want to talk about by writing "3" or "2" before the comment so it will be easy for us all talking about this. hope i made up some strong points and with them be able to rise up some aspects of a 4X that can be really great if developed well ^^

ps: sorry if my eng is not so good

I also hope they incorporate more team options into the game set up. Players are going to do it regardless so you might as well make it a feature. I liked in Civ 4 that you could do teams. Then instead of 2 players vs 1 AI vs 1 AI you'd guarantee that it was 2 v 2 which makes it a more fair fight. It always annoyed me in ES having to restart if my friend was too far away and that the AI wouldn't get partners of their own to even the scales.

exactly, and that, in my opinion, will bring much more durability over time to the game

Eulogos wrote:

I also hope they incorporate more team options into the game set up. Players are going to do it regardless so you might as well make it a feature. I liked in Civ 4 that you could do teams. Then instead of 2 players vs 1 AI vs 1 AI you'd guarantee that it was 2 v 2 which makes it a more fair fight. It always annoyed me in ES having to restart if my friend was too far away and that the AI wouldn't get partners of their own to even the scales.