The provinces at Kola and karelia why isn't it possible to discover them, Sweden had in the 14th century around 300 troops stationed there around Murmansk.
More events like allow women at the universities. An event to improve chances of getting a culture changed to the national culture or like missionaries for change culture.
If you are the only nation with your religion make it possible to swap to an other.
A poltical slider for the church, stay close to the pope or go your own way.
When infrastructure is improved allow building roads, railway with means faster troop transport.
Unlimit the population limit in cities, increase thier value every human increases the taxes, when using manpower it will mean a loss of poulation in the area where the troops are raised and the refill will be taken from the regiments home area.
Ability to refine natural resorces when tech imporves, make them more valuable.
Make cupper, iron and gunpowder/arrows needed for training troops.
Make it possible to form defensive alliances. When France is growing and makes a threat to Spain, Portugal and the HRE let them form a defensive alliance or when Sweden threating Russia and Denmark. When the Islam are threating Middle Spain, Rome, main Poland/Russia or the HRE. Unite all Christian fellows and form an alliance to strike them of.
Crusades should mean that when the pope has decided a crusade all catholic kingdoms and republics should be given the event of crusade with the options to join or refuse. Refuse should mean negative effects of your nation and improved relations of the attacked faith. Join means that YOU are in war with the nation where the crusade are sent. You are sending some manpower to the papal state witch lead the Holy Armies and the Holy Armies are cheap to pay off.