In early prototypes, I had two different strategies that were not intertwined. There was almost no reason or incentive to do anything related to the other strategy. The first strategy was to defend and kill. The second was to advance and destroy.
I divided the board a similar way. I had an enemy entry point that allowed defending players to focus their defenses and an exit point for friendly units to conquer the enemies on their own turf. Enemies and Friendly units never had to interact. The game was dry and had multiple turns of going through the motions.
Through brainstorming, "crossing the streams" was the solution. By forcing the unit types to cross paths, there was interaction and choice. The problem was the frustration and inability of the attack strategy player to never be able to leave. Over weeks, I moved the exit and entry points and even the location of the keep in order to fix the problem. If I crossed the streams too early, it was the same as not doing it at all. If it was too late, it was too bloody. I was about to give up when I tried the illogical yet simple setup of the exit and entry points being the exact same, at the opposite corner of the keep. By allowing the players to move units into the "Mountain Pass" and then choose to fight or move into the valley, the perfect solution was reached.
New players of Dragon Valley will never know the effort and time put into the simple result of the player regions.
Next up: Too Extreme