I once thought of how to make it so you can build it like you want. I found it hard to get my head around, so rather than brick troops, a minigame could help it out. The team leader is the king and will choose what happens. The minor players on each team collect "Resources" then it's up to the king/leader to bye weapons and buildings.
Just an extremly short brief with little detail, but it skims the surface of an idea.
I know it would have to have someone watching over to determin who will win, so that's one problem. Though it can be fixed and work it out it some way or another. But I like the idea of Civilisation on Blockland!
I really hope this turns out good!