This idea I have isn't specific to 2fort, but I put this together to illustrate the idea I have. Imagine if a team's base had a one-way gate at the front, with the intention that you have somebody (like Spy or Scout) take the long way through the sewers or battlements to go around and open the one-way gate so that allies could flood in. The map would be designed around this idea as once the enemy team has infiltrated "the front door" the map would be designed so that team has a tactical advantage in that immediate area (given the high ground, immediate access to the control point / intel)

I think the idea of having somebody "open the door" for their team is a novel concept. It isn't something you do in any map.