I'm really enjoying the new multiplayer game I just started. It is my third real multiplayer game, and there are only two teams. Therefore, I am immediately interested in spending my resources to scout out my enemies and planning to attack them as soon as I can even though it is only turn 10.
I'm also interested in spending my resources to help my partner, which is fun because I get to spend time talking to him and it makes it more of a "social" game than a "loner" game.
There are two teams, each with two players. If this were an "all against all" game then I would not be willing to spend any resources or any planning on how to attack one of my three enemies, but instead I would be trying to expand, research, hoard and so forth as fast as I can.
All-against-all games are somewhat more of a "race" than a "war". Each player races to get the best summons and artifacts and hoardings and whoever gets there first wins.
If you want diplomacy but you also want to avoid the effect of "all against all is a race not a war", then consider the pentagram style:
pentagram diplomacy