If you look to colonization and the overseas trade race, portugal and the dutch definitely have their rightful places as playable factions. if you look to the napoleonic wars austria-hungary has a very central role and must be in. and denmark-norway, while not a big power player, actually has something of a role in both.

doubt any non-western factions will be in, they historically lack the capability to be global powers.

so i think they should all be in. btw 10 factions arent exactly a lot, must be the least of any tw game yet?