A lot of countries are "missing" from that list since only about 154 or so countries have counties at Project-GC, almost all countries have regions (241 of 250 IIRC). The size of the country is not relevant, it's the availability of subdivisions and the availability of borders for the subdivisions.
My suggested workaround would be to use the MapRegions or MapCompare. Depending of the country and what you want to check.