The main flaw in the social sciences is there seeming inability to maintain objectivity and actually conduct valid studies by valid, scientific means. It leaves their conclusions highly debateable and questionable. More rigour, a stronger connection with the hard sciences, might help fix that.
Realistically, it is a young branch of academia, and has a long way to go to gain credibility. At the same time, it is likely one of the most important domains of study out there. A lot of potential.
If they don't start being more scientific, they will continue to be basically useless in any real way. False conclusions that fail to incorporate even the most rudimentary alternative explanations abound, making the field seem kind of haphazard and sloppy.
The social sciences are part of the scientific discourse. The social sciences are apart of what is traditionally called the soft science. This field is called the soft science as opposed to the hard sciences of physics and chemistry and to a lesser extent biology. This science is considered 'soft' because quantitative data is hard to come by. As the techniques of science advance the social sciences will become less soft and more rigorous.
Yes they should because if you are studying science in general social science definitely would be counted. The Social aspect relates to the psychology of sciences and the mind is the most complicated part of science that is not yet understood just yet. Science is a very vital part of scientific discourse.
While I believe there is definitely a place in this world for social sciences as a way to measure how to do things, I do not believe they need to be scientific discourse because they are not always one hundred percent correct. They should be used to help understand situations though.
Just because the name contains the word "science" does not mean it is actually science. Even computer science isn't really science. Science explains the way the universe behaves, which is why physics and chemistry are real science. Engineers use physics to design things to exist in the universe, not social science.