First things first: A healthy and well-rounded development of all mindsets is crucial. This is possible when we consciously build the capability to shift mindsets depending on the need. In other words, our mindsets must be the means to the ends we need/want, but not the primary driver of our actions. For instance, an overly dominant Defender, acting out of the emotional twins of fear and desire, could result in reactive decision-making rather than well-thought-out strategic thinking.
The dopamine + cortisol-driven Defender mindset is like the lowest gear in a car. It musters great power to help us escape trouble, like when our car wheels get stuck in a muddy ditch or when we fight an immediate danger. However, driving in low gear on the highway of life causes immense stress to the system, eventually causing it to break.