Unknown markets get harder and harder every year as minor leagues become richer and more professionalized. Scandinavia was possible for Morton at first because Danish football was amateur. When the Iron Curtain came down suddenly all the top players in the former Yugoslavia were free to travel and even top-level guys could be enticed to mid-league clubs in France and Germany. Those opportunities just don't really exist in large numbers anymore, not to mention the expense of work permits. The closest we had to an untapped market was the League of Wales and we know how that went.
I'm not saying there are zero rough diamonds out there, obviously clubs at all levels of football punch above their weight through creative signing every year, but it's significantly tougher than it used to be.
Therefore if the two options are "go for unknown players" or "try a sort of brute-force moneyball and go for undervalued players who can play within a system", the latter is more realistic.
Of course there are other options, this is just between those two.