a lot of people complain about truce breaking. How about having a coalition button?
Being part of a coalition would mean you have the impossibility to attack your allies. A coalition would be valid only for a pre determined amount of rounds and would need all members of said coalition to agree.
A coalition cannot have more than 50% of total troops on the board. If the coalition passes 50% of total troops, the weakest allied gets kicked out of it on his next turn.
In fog games, you would simply be aware that making a coalition between A and B was attempted, and everybody would get to know if it worked or not, and how many rounds the coalition lasts.
There would be no limit in terms of number of players joining a coalition, the only limit would be the total amount of troops.
I have no idea if this could be balanced or not. But it sure would need a lot of diplomacy negociations in game chat, i think it could be fun. The best thing is that there could be no back stabbing.