As you, I have also questioned myself how useful the General Equilibrium model is nowadays, or if it´s just an abstraction detached from actual reality.
As we have seen in class, the First Welfare Theorem, which stablishes that competitive markets tend toward an efficient allocation of resources, may be laying over really strong assumptions that do not happen in real world. Moreover this theorem supports the idea that leaving the markets alone will end in a Pareto efficient outcome. Pareto efficient just means that no one can be made better off without making someone else worse off; but, is that what we desire to achieve? In fact, it may result in an outcome that is not fair at all.
On the other hand, I understand and think that models do not need to be real, their main function is to be practical and helpful. For example, the map of the subway line inside the subway is just a straight line and does not show the curves and crossings of the road, however it is useful enough to allows us to get from one place to another. The FWT is a mathematical model and as many of these models, it is useful within narrow ranges. As a policy maker the model would be helpful in studying effects of policy changes. However we must be careful because, economic policy has a direct impact on social and political issues in our daily life.
For this I think that General Equilibrium models should not be left aside, but as you said it must be accompanied with some other theories like Behavioral Economics, which reflect better human behavior.