1. 10 million population = one plot
This is highly unrealistic looking at our own map and our real world. Look at Bangladesh, way smaller than California but it has more than twice the population; and look at the Philippines, way smaller than the Democratic Republic of Congo, but has 20 million more people. Plus, us people with 100 million plus people in their country would have to claim a lot of plots, giving our map moderator a lot of work..
2. Islands
Dafuq you say it's difficult to rp islands? I personally think more islands is better, looking at the scarcity of such natural structures in our map. Look at the real world, you got island nations like Japan, Philippines, and Indonesia having a fairly high nominal GDP (not per capita), while nations like Madagascar, Caribbean nations, and Pacific nations that have low nominal GDP but would be fairly interesting to rp. The only active nations that I see claiming islands are Biseam, Paracambi, Lodjia, Xaeth, Bakermayya, and Socram. As for the history, come on guys, if we can make a panda love story, then we can probably make a decent timeline on these with minimal retconning.
3. Plot Size.
Plot sizes of Albion, Ardia, and AK seems alright. Aranye on the other hand needs to have less inland.
4. Expansion
I don't agree with Tamora's suggestion. Just like what Achkaerin said, having an rp with a pre-determined outcome would make the rp itself feel fake; like watching Infinity War but knowing who will be snapped (or the fact that Thanos succeeds in snapping, trust me, the experience of a movie being spoiled to you is crap). I also think that players should only have a maximum of 9 plots to play with (even though I'm playing with 15 plots) as to give chance to newcomers and to those wanting to have a decent secondary nation.
5. My Suggestions
Expand the ocean between Albion and Ardia on both sides. How do you expect typhoons/hurricanes, a relatively common thing to occur in coastal tropical areas, to take shape in those small ass bodies of water. Also, don't you think that the tip of Albion is too close to the Hygelac?
PS I agree on what Tamora said on the sandwiched territories