think like this:
the core is at senior bachelor level, put that aside.
use the elective, and additional elective outside the graduation requirement to select useful courses.
which course are useful? have a look / research of the program structure in other solid master within columbia, e.g. MS Fina Econ, MA Econ, part of MA Fina Math.
2. 選修課當中的確不多經濟學的課, i.e. this means that this is not a good preparation to econ PhD somehow......and most importantly, 你要看的是, 可不可以在core+elective之外再take course, 而不是單靠required的十門課. 尤其是十門當中有五門是廢了武功的.