The justiciability of directive principles are now a dated principle. That is because just like time laws have change and they need to change and adapt to the way we live in a society now rather thenhow we lived in it before. If they can change to meet the ways of the world it will work.
Directive principles are guidelines that must inform all other laws written by a governing body. For example, the directive principals of the nation of Ireland include, "Everyone has the right to an adequate occupation", and "the free market and private property must be regulated in the interests of the common good". These directive principals are no longer cited in making laws; they serve no real function in modern society.
I do not believe the justiciability of directive principles is now a dated principle. Justiciability is simply to guidelines followed to decide if a case should be heard. It simply eliminates the matters that don't meet the criteria and I don't think the guidelines are outdated to the point that they are no longer usable.
No, the justiciability of directive principles is not now a dated principle, because we will always love justice. As long as people have lived, they have wanted rules, laws, and justice. People have always wanted to protect innocent people. Justice is one of our most fundamental needs and desires. We want to have fairness in this world.