Please consider the literature on "problem definition" and the argumentative turn in policy analysis in general. Whether something is a problem, and what its causes might be is a point of political debate.

This seems to be a very particular way of looking at the issue. I would rather say that evidence-based policy making should be the foundation of policy making. Addressing problems-to-come is one of the roles of policy making, but not the only one.

I see big data mostly related to agenda setting

Basanta Thapa political debate should follow argumentation techniques in order to be easy to analyse. The political opinions following argumentation techniques are the only ones that should be taken into consideration IMHO.

However, focus should be put on why specific problems, although well-known, have reached the status of being too costly to face...

Just detect them of facilitate their alleviation? Are these problems examined only in terms of cost? What about their social aspect?