It should be possible, Imperial Splendor has went even so far to have multiple custom tech trees for various factions. From what I understand though it is a lot of busy work. Since you seem to be the only person working on this mod, I'd say the safest bet would be to create a generic tech tree for Western factions and one for Eastern factions.
For the Western tech tree maybe it could tackle things that were issues for the that time such as colonialism and adapting to new climates and territory, cultural reforms due to the conflicts between Protestantism and Catholicism, supply logistics for massive armies, the development and rise of large musket armed standing armies, and the standardization of arms and uniforms. For the Eastern tech it could be trying to modernize and keep up with the West, cultural and religious reforms, and importing arms from Western countries.
Edit: Also the removal of forts would do good for battles since forts are horribly bugged in ETW.
Edit 2: Since removing forts would also make battles and the campaign easier, which would be odd for a 1600's themed mod, maybe make revolt chances higher for captured territory? So that it is difficult to hold onto territory and prevent a player or AI from taking over the map too quickly.