The objective of this conquest mode (or special event) is to capture a neutral point (maybe in the top of a hill or a building) and raise a flag of your faction. The act of raise the flag should take time (like in demolition mode) and after that the countdown of the capture should start.
I think this mode would be intensive and fun and also it would be cool to have some historical flashbacks.
My second suggestion is related with the first one. Why don’t use flags as equipment too? I would love to charge the enemy with a flag in my hands (and probably getting shot) and try to use it to kill some poor guy before dying like a hero or use it to celebrate a win in the top of a building (another historical flashback).
We could also have a white flag to surrender or for start negotiations with the enemy (now I’m joking or , at least, I think so).