I'm in the CSS department at George Mason University, just starting my dissertation.  Though I'm not primarily aimed at tenure-track academic jobs after graduating, I have some insights regarding the questions you have asked.

First, you should know that CSS at GMU (and most other places similar to it) are not solely focused on placing their graduates into academic jobs.  There's a wide diversity of career paths, both prior to entering and after graduating.  To me, that creates a looseness and openness among the students.  This is in contrast to discipline-focused departments where everyone is expected to prepare for and compete for top academic jobs.  In those situations, there seems to be a strong emphasis on things other than just learning and doing good research (competition, prizes/awards, getting into the 'in crowd', elitism, etc.)

Second, CSS would be a poor fit for many academic jobs (research or teaching) that really want depth and credentials in a single discipline -- Economics, Sociology, Business, or Computer Science.

Finally, there is significant growth in the number of departments and jobs (internationally and in the US) that specifically call for Computational Social Science or similar interdisciplinary degree.  This is driven in part by funding agencies who have become very enthusiastic for CSS and similar types of programs and projects.  It's also driven by market demand -- especially for social network analysis, Big Data in social science, and programmatic research (e.g. public health, international development, conflict studies, cyber security). While the number of these jobs may not be large in absolute terms,  CSS graduates could be extremely well-qualified to fill them, compared to single-discipline graduates.

Prospects with a Computational Social Science degree
I have a surface defined by values on a two-dimensional grid. I would like to find an approximate function which would give me a value for any arbitrary point within certain range of xs and ys.

My general idea is to construct some sort of polynomial, and then tweak it's coefficients by using some sort of evolutionary algorithm until the polynomial behaves as I want it to. But how should my polynomial look in general?
