about the new map:
phisical: the formation of such a continent would require a large mountain range... such as the americas are dominated by the andes range, OR by a high-altitude landmass, like africa
in any case after creating an altitude map you cand distribute the forests/swamps and rivers
political, most borders are based on phisical characteristiks of maps, rivers, mountains
strictly regarding your map:
1: create a mountain range that goes from the north east along the eastern coastline to the south weast (this would create a ogical border and a fixed frontline in case of wars, getting over the mountainss being a real problem
2: build rivers acordingly, so moving north ans south would offer the deffender good deffensive positions
3: lakes, build some lakes, they will provide even more diversity to a war
4: islands, build more islands, or even a small landmass to the east where you would create an island nation such as england
5: less, countries, it would make the gampley enjoyable when there is a real threat and there are not may AI wars, also it will make your event-making work easier, and the result will be much better
PS: based on your map proposal, I can design a geological realistic one, if you like