I agree that a general overhaul should be done considering the interplay between industrialized and unindustrialized nations. Aside from Africa and the Pacific, this era was about indirect colonialism. Vikky 2 should steer away from scripted events in situations like the intervention in Mexico, the opening of Japan, and the Boxer rebellion. Instead, World Powers should be able to exert influence and provide capital and technology in less advanced nations. The unindustrialized nations, as Japan and Thailand did historically, would be able to use the relationship to their advantage, advancing themselves while resisting imperial intentions. Otherwise, as happened more often than not, the relationship would turn into an open door in which the World Powers can exert imperialist agendas.
For example: an uncivilized country wants to modernize, so it has the diplomatic options to request military advisors, economic advisors, technical knowledge, and so forth. However, each advisor gives the World Power providing them an increased percentage chance to make that minor it's puppet.
OR
An unindustrial country opens itself to foreign investment. Industrialized nations can chose to be For or Against investment in different areas (perhaps individual nations or by continent). If they are For investment, their capitalists will spend some time investing in that nation and thus get profit from those factories which the World Power can tax. However, this will give the World Power casus belli to intervene militarily if its investments are threatened (much as IRL).
Lastly, i think its very imprtant for Vicky 2 to have a trade system more similar to HOI2 than Vicky 1. It would be a lot of work drafting individual trade agreements, but the fact of the matter is that there was so much emphasis placed on who was and wasn't allowed to trade in certain places. Entire wars were fought over it and nations that control one resource should be able to decide weather or not to sell it to another nation. The trade system should reflect this historical situation.